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 stream live without cable on Tubi, Sling TV Freestream, Xumo Play, freevee, Samsung TV Plus, Local Now, or Philo Free TV.
The cheapest option to watch live is Philo Free TV for $0/month.