I pay 10 bucks per month for my phone plan AND high speed internet at home

I can get a cheaper-than-normal phone plan from work (10 bucks instead of ~30). With it I get unlimited internet, calls and texts.

Me and my girlfriend both work from home, so we still need internet at home (hotspot doesn't do it). So I got a second SIM card with my phone plan, bought a used 4G router for 50 bucks, and now we have "free" home internet at 150-200mbit/s.

Usually a second SIM costs ~5 bucks per month, but even that would still be worth it. The cheapest home internet plans I find online start at ~40 bucks for 50mbit/s.

In my country it's normal to spend >100 bucks per month on your mobile plan and home internet, so that's a win for me.

Check with your mobile provider, if you can get a second SIM. You could save a lot of money.