Saving $10-20 (or even 10-20%) buying a used part isn't worth it. There's too much risk as a buyer because you have no recourse if the part is not what it was purported to be, or if there is any damage or defects.
When I've sold used parts, pricing is a balance of the above, as well as how badly I want the space in the garage back.
Following is a short list of things I've sold over the past year that have been great deals for the buyers because I wanted the stuff gone...
- Brand New Hedman Headers (#88300) for 65-66 Mustangs, New in the box (only opened to take pictures) - $100 (less than 1/2 the price of Summit Racing)
- Craftsman 33 gal. Air Compressor, 6 hp. Horizontal Tank - $150 - Over 10 years old, but like new and about 1/3 of cost when new.
- Variable Speed Free Standing Floor Drill Press - $60 - Probably 30 years old, but worked great.
In all cases, the buyer was happy and I was happy!
Anyway, I'm with copracr. Unless it's a smoking deal, it's a complete waste of time to even look.
One last thought... It doesn't hurt to make a lowball offer. I've asked sellers if their priority is getting their price or getting rid of the item, and just told them "if you want it gone today, I'll give you X
for it." Some have politely said "No thanks!" and others have said "Ok." One said, "Ok, but it's gotta be gone by 6:00pm tonight." If you don't ask, you don't get!