How do i get cheaper USDT/BUSD?

Please tell me if I'm doing something wrong, i don't consider myself great and i want to learn more.

So I get usdt through p2p from other people (to then get coins). And as you know it's an open market where sellers place their prices ranging from 0.993 to 1 (more or less).
I was wondering one day, where do they keep getting usdt from and if i can just get some for 0.99 and sell for 0.993 for example?

Any advices/tips are appreciated.