#15(?): if the ad says make offer but does not include a price it will either be a great deal or a major hassle and not worth the time to go see it.
When I post something I'll put in a price and then sometimes add in "if you don't like the price then make an offer".
#16(?): if there is no pic then there might be a reason. If someone can figure out how to post an ad then they should be able to figure out how to post a pic.
#17(?): if the poster writes in texting lingo then the deal iz gon 2 b uh mjr hazl 2 mak