The concept
A prop firm ( for proprietary trading firm) lets you trade with their capital in exchange for a share of your profits — after you prove you can trade within their rules.
How it usually works
You pay a one-time or monthly fee to take an evaluation. If you hit a profit while respecting all rules (, daily loss, consistency), you get a 'funded' account and can request payouts.
Simulated funding
Many prop firms use simulated funded accounts — the payouts are real, but the account isn't a personal brokerage. Always read the small print.