Ah, that’s a trick question! All clients pay for their design contests up-front.
After you’re selected as the winning designer, upload your final design files as soon as possible. Once the files are approved by the client (in the Design Handover stage), we’ll add 99designs credits (also called "earnings") to your account in the amount of the stated prize.
You're able to request a payout of your 99designs credits at any time as long as your balance is above $25 to an account and in a currency of your choosing.