hahaha, I made a post something like that once... trying to sell stock tires. I pretty much said "cash talks, bs walks, will not trade for 317 tuxedo t shirts, show up with 100 bucks and you leave with the tires". One guy jokingly told me he'd give 80 bucks and two tuxedo Ts because he gave the rest away already, I figured that was a fair offer.
I do get really tired of the halfwits who see a post on CL and completely ignore 90% of it, or agree to buy and then completely disappear. I've even had people agree to buy, completely disappear and ignore all messages, then give me the third degree days later when they find out I sold my stuff to someone else.