Yes, there are several ways a skilled player can make money playing blackjack under the right circumstances. Off the top of my head 3 ways you can do it are promtions/coupons, card counting, and tournaments.
Promotions/coupons is by far the easiest way to make money at a casino, they're literally just giving it away. Any ploppy with a vague notion of basic strategy enjoys a monstrous advantage using a matchplay, win card, free ace, etc. Advantages of this play are that it requires no skill and really no bankroll. Disadvantages are that it is completely casino determined so it is limited and not likely repeatable. Unless you live in a competitive market ie. Vegas you'll probably spend your advantage on gas. Many people on this site claim you can take advantage of online casino promotions, but I have no personal experience with this.
Card Counting is a mathematically proven method that allows a skilled player with sufficient bankroll and favorable conditions to attain an advantage in the long run. Advantages include repeatability and exponential return do to increased bet sizes. Disadvantages are high initial investment both cash, several thousands, and practice. Also variance is high so it is not for the risk averse.
Blackjack tournaments are a third way you can make money at blackjack. Obviously a skilled player has an advantage at the game. I've only played in promotional tournaments that were either free or had an associated promotion with an expected value higher than the entrance fee. Especially at promotional tournaments most of the players were ploppies so any basic knowledge of strategy would increase your expected value.
There are other ways to make money at blackjack, some legal, some illegal, but these are the 3 easiest ways I can think of.