[Shoe]

There are very few people who can make a lot of money at these games by playing them straight up. If you have 24/7 to devote to the game so you can give yourself the best character possible, and don't get extremely bored by running around farming the same exact things day after day after day, then this might be for you. Otherwise, to make a lot of money you need to find an exploit or a very well guarded secret that you can take advantage of to make any decent money.

EDIT: In most of these games (by this I mean the most popular MMORPG's -- check selling prices on ebay or playerauctions), you probably could make $5-$10 per hour once you get a good enough character. But making more than that becomes a struggle unless you really know what your doing. And if your playing to have fun, you'll probably spend all of your profits. You also need to be able to find multiple ways to make good money/items in the game, as what works today, could get nerfed tomorrow!