A lot of internet providers around the world love to have data cap limits on your internet. If you want to go over some will charge you per GB or even TB (if you are reading this from a time period where TB is the new standard).
It makes sense though, right? I mean just like when you use more electricity, natural gas, or water you should pay more. More usage = more costs?
In this case, no. Internet providers are just being as greedy as they can. Well, you may say, they have to maintain lines and pay for new infrastructure! Usually wrong again. A lot of that is paid for cities or federal government grants. Basically your taxpayer dollars pay for a lot of the infrastructure, so that internet providers can then charge you for using that.
Well what about the servers that have the information that I connect to read, play games, watch movies from? Those servers are not provided by internet providers, those are from other companies who pay internet providers to host them, some of which are limited by the cap too!
So basically the only reason for data caps are allowing you to pay to go over is so they can squeeze even more money out of your pockets.