I've made over $100,000 on flippa.com so i'd recomend trying there. Some of these are great, but with bitcoin being such a small market(in terms of the domain industry) I couldn't see more then 4 of these go for more then $500 in my opinion.
I also have made well over $100,000 selling these "$500 worth names". Also I basically sell names to end users and don't care about the domain industry (most of it failed to see Bitcoin's potential and dismissed it as a fad until I had grabbed hundreds of the best names), so Flippa isn't my thing.