I suspect that demand is low and supply is high right now, due to gas prices -- people willing to drive economy cars bought them when gas was $4/gallon and lots are selling now.
Your craigslist ad says "trades ONLY". You should edit that.
Hypermilers will want it with VX rims, not steelies, so that takes a chunk of value off of it when advertising somewhere like this. You should consider replacing the speed sensor yourself; I think not having that problem would be worth a whole lot more to most buyers than knowing that it's cheap to buy the part that may or may not fix it.
You might also want to provide more details about the body damage and the repair quote.