Advice about networking(new labber)

New labber here, I'm a student who lives in dorms on weekdays and home on weekends. I'm trying to get myself some kind of vpn to escape the school network and a (probably) minecraft server.

The problem is that my house only has cat5e, and it's not going to change. There's a cheap router connecting the outside world to our home, and another cheap one in my room(the routers are connected). Will the server and vpn use up the bandwidth? How can I keep it secure?