Cities could be much more polluted since in theory everyone over 18 could afford a car. And the numbers of trucks and planes would much higher. However laws could be created in order to determinate who could acquire a car based on certain civil and demographic features;
People would probably be much lazier than they are. I read on Reddit about why money exist and someone said that humans are also animals and will do the least they can to survive and need some sort of "pressure" to be stimulated to do things. So he said that without money people would realize that they could have a good standard of living without doing anything to anyone. I did not agree with him but it was just his opinion.
I am not talking about post scarcity and resource based economies like in Star Trek which they eliminated scarcity and the need to work using high technology and Artificial Intelligence. I mean a world with the same technological level as real life but without any money and without barter as well. People would work and consume without the need of any means of exchange. Would everyone accept to work for free?
A post-scarcity economy
Goods are produced by automated factories, by robots clever enough to require little supervision but not smart enough to demand civil rights and their salaries. (There might be other robots who get those, but not on the factory floor or goods distribution centers.) Read e.g. the Culture series by Iain M. Banks for an example.
Powerful social constraints
In theory, people are free to take what they need and only to contribute what they feel like. In practice, taking too much or working too little makes the neighbours upset, and one has no right to be invited to their parties.
We're a site for building fictional worlds, so the latter option is much nicer because it offers more adventure potential. An adventure is someone else in trouble, preferrably long ago or far away ...
In a normal economy, the interaction between supply and demand works as a distributed information system which by and large makes sure that producers allocate resources to what consumers actually need.
But in a communist society there is no money. Since there is no money, there are no prices. Since there are no prices, there is no way for production to be informed of what's needed to be produced. Since there is no way for production to be informed of what's needed to be produced, you will always have overproduction of some things and underproduction of other things.
In principle, a communist society is supposed to overcome this problem by employing an all-powerful central planning organization, which uses pervasive (and invasive) sources of information to learn how many size A bras are to be produced in the next quarter, how many size B, how many size C and so on. Unfortunately, this doesn't work, from both practical and theoretical reasons.
Long story short, in the absence of prices the central planning organization cannot possibly know what is the utility to be associated with each and every item that could be produced. What they will have to do is make arbitrary choices, with zero hope of ever getting it right...
Some goods and services are inherently scarce. There is only so much space available on the sea shore for houses with an ocean view; there is no way to give such a desirable house to everybody. There are only so many seats available at a concert. There are only so many tables in good restaurants.
The point being that in a normal economy highly desirable and scarce goods and services will command higher prices, and people will have to prioritize their resources if they really want them. In a communist society there is no money, hence there are no prices, and allocating those desirable goods and services can only be done by decree.
Since there is no money, production needs to be commanded from a central authority. In a normal economy, each and every producer is independent of any central authority, and they thrive or fail on their own, with little risk of bringing the entire economy down. In a command economy, when the central authority fails, and it will eventually fail, the entire thing goes to pieces. The sad truth is that the State Committe for Planning is a single point of failure, and it is guaranteed that sooner or later it will fail, because humans make mistakes and unexpected events happen. And then you have a revolution...
In a society without money it is really really hard to motivate people to do anything more than the bare minimum they can get away with. Quality goes down, progress slows to a crawl, maintenance becomes perfunctory, and eventually a point is reached where the entire economy is a heap of disfunctional rubble. And then you have a revolution...
Funny thing is, in all known societies, when there is no official money, people will pick one or more commodities and use them as money. Packs of cigarettes, half kilo packages of ground coffee, something. But you will have some sort of unofficial currency, because see point 2 above: some goods and services are inherently scarce, and you must have something with which to bribe the bureacrat who allocates them.
Within a small group, social bonds are sufficient to have everyone contribute in some way, and groups will expel members that refuse. In such a setting, micro-accounting with money is overhead that brings no real benefit, as it requires assigning prices, a tax-like system for redistribution towards communal projects, an insurance-like system for redistribution if someone becomes unable to work, and several other institutions to manage the system.
Trade with other groups can be organized similar to exchange within the group, as basically a gifting economy where individual transactions aren't accounted, but people have a general sense of whether the relationship is fair (which can still be unbalanced, e.g. if one group has a bad harvest).
While b-5 knew perfectly well that the food supply was perilously low, he couldn't stop from slacking off a little in cultivating the mold gardens. And even if the Queen ended up starving them all with her (mis)guidance, there were other colony-cities. 851 was doing quite well, or so he had heard. And, besides the other '51' communities, there were also the '48' and '52' groups. And, he supposed, some surviving '49' colonies. As much as b-5 didn't like to think about the 49's.
The slow-down pheromones were great for making sure the community did not overwork itself, but what sort of Queen kept sending it out in the middle of a famine? When everyone was aching so much to work harder?
Please note that I came within an inch of voting to close this question as opinion-based. I'm only answering it because your specific question, "would everyone accept to work for free?" has, IMO, only one plausible answer.
"We shall execute our king instead, sir, and exalt our tailors," said Chauvelin in Baroness Orczy's The Scarlet Pimpernel. To which Sir Percy replies, "More's the pity. Then your tailors will rule the land, and no one will make the clothes. So much for French fashion, and French politics."
The only way for such a society to exist is for nothing to be available to anyone that isn't a subsistence need. Except that isn't possible, either. As soon as someone's job allows them to use a pickup truck, someone whose job doesn't allow it will want a pickup truck. As soon as someone is given a new car, someone with an older car (no matter how new) will want a new car. And you can't have red cars and blue cars because someone with a red car will see someone with a blue car and want it. You can't have people with curly hair and people with straight hair because... Is this making sense yet?
Training humanity to accept the lowest-common-denominator when it comes to living would require training them to accept the drudgery of effort without finding the joy of life. As soon as someone tells a friend across the country that they saw a beautiful butterfly, that friend will want to change locations because (true or not) they will believe there are no beautiful butterflies where they live.
Publius Ovidius Naso wrote "Fertilior seges est alenis semper in agris" (the harvest is always more fruitful in another man's fields). Which is where the modern proverb, "the grass is always greener on the other side of the fence" is believed to have come from. What both mean is that it's human nature to believe their life would be better if they have something they don't currently have.
Which means no one can fix the machines when they start breaking down... because that depends on the innovation your society cannot have that would permit even the possibility that everyone could work for free.
My thanks to @CodesWithHammer for helping me expand that example. At the time I posted this answer, the U.S. government had created an artificial condition where a skilled laborer refuses to work because all his/her needs are met without labor. Whether or not the employer could, should, or would pay more to overcome the "economic inertia" created by that artificial condition isn't relevant to the question. What is relevant is that the workers could have easily returned to work "for free," contributing their skills for the greater good of society as there were (and there were) people in need of those skills. Given the choice to work "for free," they chose to stay home - thus making my point.
There is only one way to make this work on a large scale, and that is extensive slavery. Otherwise there are always many very important jobs that no one would do without getting a significant reward. Sewage work and waste treatment are gross for everyone, woodcutting or such are too dangerous to do them without immediate need.
If slaves produce all the required goods, the non-slave population can live in wealth and splendor, free of the worries of money. They just do the prestigious stuff, research, art, architecture and such, whatever they feel like on the day.
The slave caste needs to be so suppressed that they don't even think about revolting, either through the incentive of becoming free if they work hard so that they can be on the other end of the master-slave relation, or through so much terror over centuries that their will to be free is essentially non-existent. They just do whatever they are ordered to without question. Since slaves in such a society are essentially dehumanized, they don't count into "everyone". Everyone (who isn't a slave) has everything they need.
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