The value of a domain without content is mostly subjective. A few things that can make a domain more valuable
• It’s short - a domain with 3 or 4 letters is valuable. 5 letters is better than 10 is better than 15, *generally speaking*
* Real words - this can trump the shortness, e.g., GrumpyCatAustin is more valuable than GCAustin. Real words can also help tremendously with SEO.
* Demand - <this month’s hot topic>.com might be valuable now, but may be worthless next month.
That said, it really comes down to what it’s worth to you and what you can afford. I own a bunch of domains I haven’t done anything with. I’ll get offers from time to time. There’s one that many people are interested in - if someone offered lots of money for it, I might just take it. OTOH, if someone had a really cool Make the World a Better Place kind of idea, I’d be inclined to hand it over at cost.
Julie