US (CONUS) satellite TV options are DirecTV and Dish Network. Netflix is a streaming-only service so you need an internet connection for it. Technically, 4G can handle it unless there are multiple users connected to the same tower, but, as you know, it comes at a premium for the amount of data required (roughly 3 GB per hour for HD video programming). One would hope that Wi-Fi would be an option but I've never run into public (especially marina-based) Wi-Fi that had enough bandwidth. Granted, at my home slip I can do it but that's because I installed the Wi-Fi system and am the only one using it! If a marina has a cable modem with 30Mbps (a typical commercial account with Comcast) and more than 10 boats are trying to stream movies, it ain't going to turn out well!
I don't think you're going to be in much luck for NetFlix on your boat (unless you stay in your home slip and have great Wi-Fi). But satellite TV does give you some options. I have Dish at my home so the boat only costs me an additional $7/month for the receiver. You'll need a satellite dish antenna to receive the signal. A rough idea of options:
Stationary dish mounted to a piling: $100.
Ugly and you can't take it with you (easily).
"Carry out" dish (not in-motion) that you set on a pier - $300-$500.
Would work decently mounted on a boat if tied to a floating pier. These units will acquire satellite signal but do not keep it if in-motion or at anchor.
Marine-grade dish that mounts on your boat and can "track" sat signal:
$900-$15,000. These work in motion at anchor, in a slip, etc. Lower end functions fine state-side.
Sorry, you asked for it!