Asking prices on ebay/craigslist mean nothing. There can be tons of posts asking for $1k for the same Bose system, but if no one is purchasing it it doesn't matter.
Your best bet is to look at completed sales on ebay. Your local market may not support as high prices as ebay, but if you are close that should be good enough.
Also, people on craigslist love to lowball. I have a board game that will easily sell for $150 on ebay (shipping would be a pain though as it is big), and people were offering me $50 on craigslist (probably so they could sell it on ebay). So, only sell low if you just want to move it fast.