Money is just one way of establishing "trust clubs". Time is another. For free-to-play games, you could make it so that users are peered with other users who have put in the same amount of time into the system. So if you've gone a whole year without being flagged for cheating in the system, you'll be paired up with other users who have also gone years without being flagged.

If you create a new account, you'll be peered with other new accounts (low trust). Still possible to cheat, but the cost is very high (years of effort to get accepted in the best trust clubs)