Jukie,
Your post should be in the Tech Support section, so the reps can address it there. Hopefully one of the mods will move it there.
As for data usage, it happens when the people in a household use the internet. Anything you do on the internet uses data; anything connected to the internet will use data, sometimes automatically, like for updates. Data can also be used by smart devices, such as smart TVs, even when you're not using them, as they may be connecting to the internet for updates or other things.
If you have anything set to automatic updates (phones, computers, etc.), that will also use data even when you're not there. And then of course there is what you and your daughter do: surf the web, do homework, maybe stream something, upload or download stuff, etc. All those use data. Some things use a lot more data, such as streaming and things like Skype or Zoom. Those will eat data very fast.
Hughesnet sells us subscribers a data plan. The plan we buy has a certain amount of data for the month; say 75 GB. It is our responsibility to budget that data so it lasts the whole month. For a 75GB data plan, a household would only have an average of no more than 2.5GB per day, or the data will run out before the end of the period and they will be throttled. If a household likes to stream, 2.5 GB can be gone in a couple of hours, and if they stream every day, they'd be out of data within a week.
Since you're out of data in 3 days, it's possible you and your daughter are doing data-intensive things like streaming. If so, you will have to change your habits to use less data.
As for the extender, I would use the one HughesNet makes. That one's designed for their system, and I don't think it uses any data.
If you stream, make sure you're doing so at the lowest definition, so you will use less data.
Every day, check your system control center or the HughesNet app to see how much data you have left, and adapt accordingly. Since we don't get unlimited data, we have to budget it so it will last the whole month.
No, you can't set the data speed, though that'd be cool.
Yes, once you run out of your monthly allotment of data, you are throttled until the end of your billing period unless you buy tokens.
What devices are you using? Laptop, desktop, smart phones....? How are you using these things? How much do you or your daughter stream? It is up to us as users to monitor and budget the data plan, and it can be a bit of detective work to figure out what's using data. When more than one device is connected, each of them is sharing in the data bucket, so each of them is using down that bucket. So if you have 75 GB per month and 5 devices connected, they are all drawing from the 75 GB bucket and this will use the bucket faster.
Other providers in rural areas might also be a satellite company -- it would be the same thing, a limited amount of data that you would have to keep an eye on so it doesn't run out. Some phone providers also sell packages, and you could try them and see if they work better for you. Make sure you understand what all you'll have to pay for. Verizon, for example, is quite expensive, much more than HughesNet, though it might work for you. In my area, Verizon doesn't work very well due to the terrain, so it's not trustworthy. HughesNet works much better. In your area, things may be different. Before you jump ship, go on the Web and search for internet service providers in your area, and investigate each one deeply. Read reviews, read complaints, and inform yourself of prices for packages and services.
You mentioned tokens, and yes, if you have to buy them often you end up spending a lot of money. I wanted to share a price comparison for tokens, each providing 1 GB of data: HughesNet charges $3 per token. Verizon charges $15.
Hopefully others here will chime in with more suggestions, and hopefully the reps will also chime in and provide more assistance.