Subscription rate: $14.99/month
Pro: It's not TV. You get full access to all HBO shows (as soon as they air) and HBO movies, and there's simultaneous streaming, which makes account-sharing an absolute breeze.
Con: It's pretty expensive for just one channel.
Subscription rate: $10.99/month with Apple, Roku, Android, PlayStation Vue, or Amazon Fire devices, or an additional $8.99/month added to a Hulu or Playstation Plus subscription.
Pro: It's the only place to catch a few more big-name prestige shows, like Homeland, Billions, and The Affair. There's also some movies, but...
Con: It's not a stellar movie selection (Chappie, anyone?). And it's still pretty expensive.
Note: Most major networks do have some kind of old-school website where you can stream their shows next-day if you have a cable provider login. Link your (or, ahem, your parents') cable subscription to their logins at no extra cost.