One thing is certain, you cannot depend on a campground WIFI for your internet needs or streaming television even if the campground offers WIFI service. Why? Because the bandwidth is always questionable with many others connecting to the same service, and it seems to always fail or lag or go slow when you need it the most.
Being self-sufficient is the way to go. If you boon-dock (especially in the Western States), Starlink is the way to go when you are isolated from civilization (at least, out of range of a cell tower). If you are primarily a campground person, then most of the time you will have cell phone service. And if you have cell phone service, then your phone's wifi-hot spot is probably the best arrangement there.
Now, phone wifi-hot spot plans cost all over the charts too. As others have pointed out (above in the posts), T-mobile, Visible, AT&T, Verizon are probably your best options, especially if you already have one of these plans.
For us, we have 2 AT&T phones we can use with "unlimited" data on both. We've never been throttled. And then we have "Visible" on a dedicated ZTE $79 (one time cost) phone that is used ONLY for the Hot Spot, and we never use the phone, text, or anything else. It just sits there, like a modem and then we have a router hard wired plugged into the phone.
The router sends out a wifi signal and multiple devices can use the router's wifi signal at the same time.
We use a small router ($19 one time cost) plugged into the ZTE cell phone and Visible monthly plan is $40. That's it. We can easily run 2 streaming ROKU television, 3 computers (attached to work, including Skype and Teams meeting at the same time) and an I-pad, all at the same time, working flawless. AND never throttled. Visible is truly unlimited. And the portable "router" has a range of over 300 feet, enough we can have the phone and router set up in the camper and still have good wifi service in our house. In fact, it worked so well, we let our neighbors in their house tap into it when they had problems with their internet service.
Since our initial cost was $40 a month (and can be stopped at any time and restarted at any time) we are still at the $40 level after 5 years now. And the nice thing about Visible is, it is not dependent upon identify your current location. If you get phone service, you are "in."
It's funny though, because Prime and Roku and Tubi and some of the other stations have commercials on their programming. This last year, when in Indiana, we got political candidate vote-for-me advertisements from Indiana candidates. In North Carolina (same shows we are watching), it was there North Carolina political vote-for-me commercials. And then in Louisiana, we got hit with Louisiana political "vote-for me" commercials. And the grocery store and the ambulance chaser lawyer commercials all turned "local" too. THAT is still weird to me. But the viewing show, was exactly the same.
For local news, we switch to the other television for over the air. (Yes, we have 4 televisions in the camper... 2 are Roku, connected to the WIFI and the 2 original that are not "Smart" they are connected to Over-the-Air antenna with no internet service.
Note: When the situation is just right .... we'll take the small Roku televisions outside and set them up. With the camper (Visible) wifi signal, there are no additional wires needed, just a wire to plug the television in. It's nice NOT being tied down with cables and wires, especially when outside and sun glair forces us to move to a different spot so we can the picture. THAT is the advantage of having a smaller portable, movable Smart television that's not attached to a wall. You can set it up anywhere. Even with our Visible system, we can take the ZTE phone and the portable router and the Roku Television (or our computers) to motels, picnics, and even overnights when not camping. (something to think about there).
