With the legalization of sports betting in multiple states, and many more on the horizon, the amount of betting sites available in the USA is increasing every month.
For example, in New Jersey, where sports betting started June 14, 2018, there are already 13 different online sites to use, as well as 10 physical buildings. Draft Kings Sportsbook was the first site to take bets on August 6, 2018, followed closely by Sugar House Online Sportsbook Casino (which was the first gaming operator to have an online site.) The next two to open were FanDuel and 888 Sports. BetStars is one that has very good reviews, and is very fan friendly, as is the FanDuel site.
The best thing to do, to find the best odds, is to get more than one site on your mobile device, so that you can search around and compare the odds. There will be certain sites that show slightly different odds, some of which can be in your favor.
Expect the number of sites to explode over the next year or two. As with other new technologies, sometimes the best ones are the ones that have been around for awhile and have ironed out all the kinks in the app. But the new apps usually have some great offers when they launch, to try to bump into the market, so make sure to pay attention to their launches.