There are a number of casinos that allow US players to play on their casino that also allow players with matching bonuses to play Blackjack to offset the play through required for release of the bonuses. The Internet can be used to find these casinos. One must read the rules carefully to find out if the bonuses can be used to play Blackjack or not. Many casinos have a limited list of games on their site that will be eligible for play with bonus money. Usually the slots are available since they do not take any skill to play. Games of skill and strategy are not readily chosen for bonus play. The casinos would rather have only games of pure luck played as the player is less likely to win with the free money. Playing games with higher house odds is not favorable to the players that are trying to work off the bonus money requirements. They may satisfy the playing requirements, but the chances of increasing the stack are lowered. With less chance of winning the bonus money will be dissipated and the player will have to redeposit sooner. Casinos online are run by smart people who know the breakdown of bets and which ones are best for the house. They much prefer the games with better house advantages than those the can be played at nearly no house percentage in their favor. For this reason look at the games the site is willing to let the player use to play bonus money. Some sites have absolutely no restrictions and others are restricted to just a few games. Players would be wise to play at the more liberal sites than those with tight restrictions. Search engines can be used to find sites that offer bonuses and the best rules.
It is worth using the search engines to find casinos that have favorable rules, but also allow US players to play on the site. As most players are aware, many of the better UK casinos are out of bounds for USA players. So this restricts the list even more of those casinos with good rules about bonuses. It does not do the USA player any good to find a casinos with good rules that stops USA players from playing online at the casino in question. But an Internet search will still find casinos that qualify for USA players.