in low levels money is the problem.
If you don't want to spend extra, the solution is to build your team with 28-30 y.o. 5* players and replace them every season (or two for some of them) - and only few young.
If you want to spend (very) few money, there is a good offer that pop ups from time to time (a small pack for 1$).
The best investment is to buy a recommended player who needs only T. Check and compare from the list and the bank for someone who's token value is bigger than the loans.
Participating in CH.L. will start to give some good money.
Don't bother with friendly games. You stadium is still small and you won't have good money from that.
This is a good solution only if have bigger stadium.