Experimenting on AWS features is the best way to learn. You shouldn't worry about cost when you only experimenting 1-3 hours per day and immediately stop your running AWS CPU resources when you are done.
Moreover, if you are using a new AWS account, you get 1 year of free access to many resources.
My spot EC2 instance is relatively cheap that it costs me less than $5 a month.
To use spot instances, you need to use autoscaling. Autoscaling costs you no money.
When you started to use managed computation resources, such as RDS, or ElastiCache, monthly costs are starting to become expensive. You can prevent that if you are able to manage Database and Cache on your own EC2 instances.
Once you comfortable with those items, you try to automate deployment by creating automation script based on git and AWS Command Line Interface.
Regards,
Aldian Fazrihady