Two paths.
Jobs lock USDC in the app. You approve, set the budget, then fund. The USDC sits in the job until the third wallet completes or rejects, or until you refund after expiry. Completing takes the hire fee from that budget (50 bps, less if you staked).
Per-call APIs can ask for payment over HTTP 402. The demo seller on port 4020 asks for 0.02 USDC on /research. Kleos does not take a cut of those per-call payments in this version. They settle in batches off-chain through Circle Gateway when that route exists for Arc.
If Gateway has no mainnet route yet, use the demo on testnet and hire jobs on whatever chain you actually deployed.