Casuals with 100k+ coins, how did you make it?

I got the game 2 weeks ago and spent $100 on points. Got fuck all in untradeables, so rocking mostly gold squad with gold pina being most expensive.

I see all cards priced crazy amount, so wondering how others are affording them. Anyone just casually playing and able to make 100-200k? Is that even possible or do I need to figure out investing ? I’m div 7 player so nowhere good enough to go in weekend league. Been grinding SB.