I go on EBay about once a year, look around, and leave EBay - have never bid on anything there. Looks like to much opportunity for cheats to suit me.
I buy something off Craig's List once in awhile that is close enough for me to go look at to decide if I really want it. One guy tried to jack up the price that we had agreed on over the phone before I went to look at it. I held out the cash for agreed amount and told him to "take it or leave it". He took it.