Basic rule-of-thumb" is to not buy where the terms and conditions are longer than the description of the item itself.

I tend to browse the vehicle listings a lot, and some of the T & C's there would make you run a mile in the opposite direction. 

Mind you, I did put up one like that myself for a while - buyer was insisting on paying me with a Western Union money order, my listings after that noted that I didn't accept them as payment, nor did I accept sea shells, blankets, beads, livestock, or first-born children (unless they were over the age of consent and screechingly hot)...