I've just recently purchased and set up the equipment described on this blog:
Signal booster and more!I'm on the road on a 6 week trip, and I've used it a couple of times and it's working well. I like adding a layer of security for when I have to do a few banking chores.
If you watch the video, you'll see that it requires a certain level of computer skill, but if you can handle it, it's a great option for under $100. But, as clearly pointed out, all you are doing is amplifying the campground signal. Most of the time, there isn't anyway that you are going to stream video using the internet signal provided by campgrounds.
This is just one option. I don't have any experience with tethering via a smart phone. And, I've never wanted to get into the expense of any dish based system.