I've flipped several myself, some with sites included and some just blank. It's really not that hard as long as you use common sense (so many don't, which is why it's so easy). Do your checking for valid stats before bidding, and make sure either to wait awhile before selling on the same market, or switch sites when looking to sell.
It doesn't bring in fast money, i'll admit that. I'm sitting on quite a few now, but if I actually got to work on them i'd be fine come the next PR update.