The USA channel was originally formed in 1980 as a national sports channel, the first of its kind at the time. While it still somewhat carries that branding to this day (it's one of the major channels where you can watch WWE shows), it also has since expanded into reality programs about travel, business, and race competitions. Oh, and bonus: it also occasionally airs procedurals like NCIS and Law and Order thanks to parent company NBC.
You can watch USA on Fubo, Sling TV’s Blue Plan, DirecTV Stream, Hulu with Live TV, or YouTube TV.
The cheapest option to watch USA is Sling TV’s Blue Plan for $45.99/month.