Most of the free bitcoin things, like mining or doing various promotional things in exchange for small amounts, are nickels and dimes, not really worth the effort. Had you mined some when it first started and saved them all up you would have been rich right now but those days are long gone. The only practical way to make money on them is to buy and sell, buying through a low cost format like direct deposit and selling through a higher cost one like PayPal. The catch being that PayPal can be charged back if the buyer is a scammer and doesn't actually pay. So you have to sell only to people with good reps on the sites. I don't know how much people actually make from it, probably not that many people buy through PayPal because it costs more, as I said. At least not people who buy frequently and therefore have good reps, maybe a few newbs.
