Two years ago I bought a bicycle for the road. Skinny tires- that kind of bike (and no, I do not ride in spandex). I was able to ride on Saturday mornings, but last year, and this year, I won't be able to. So I've been trying to sell it on Craigslist. And I see things a bit differently, so my exchange, or lack thereof, using Craigslist (and ebay) have brought me a few ideas:
1) eBay and Craigslist are basically online mediums for selling quality used/one-offs/repaired items where normal retailers can't (or won't) sell.
2) eBay and Craigslist are basically online garage sales. You post for free, you should get stuff for free. Especially if the ad says "U-Haul."
Given the two options, which one is the seller, and which is the buyer? In my experience, I've bought very cheap (but completely functional) and nearly full price for items. It depends what you buy, or what you are willing to give up (quality, price, time).
However, just because it's on eBay or Craigslist does not mean it's completely dirt cheap, nor should a buyer expect to offer, say, $400 less (about 1/2 the asking price) for a slightly used (less than 200 miles), never ridden in the wet, kept indoors, carbon fork, SPD pedals-equipped Trek road bike. With a cyclometer.
OBO stands for "or best offer," not "take it up the tailpipe."