Who pays the network fees?
Every transaction on Algorand pays a small network fee in ALGO. The fee on paying for data is covered for you, and PortMula pays for setting up your agent's wallet. Everything else your agent signs pays its own fee from the ALGO in its wallet, which is why PortMula puts some ALGO there at the start.
Paying for data
When your agent buys a service, it pays in USDC through x402, and the network fee on that payment is covered: your agent signs only its own USDC payment, and the fee is paid by another part of the payment. So buying data does not move your agent's ALGO balance. What you pay is the service's own price, shown on the Services page.
Setting up your agent's wallet
A new Algorand account needs some ALGO before it can exist, and it has to opt in to USDC before it can hold any. When your agent's wallet is first set up for a deposit, PortMula sends it that ALGO from PortMula's own funds in one step: enough for the network's minimum balance and the USDC opt-in, plus some extra so the wallet can pay its own fees later. PortMula pays the fees on that step. Once it arrives, that ALGO is yours, and a full withdrawal takes it with everything else.
Trades and everything else your agent signs
A swap, a pool deposit or withdrawal, starting to hold a new coin, and a withdrawal to your own address all pay their network fee from the ALGO in your agent's wallet, or in connected mode from your Pera wallet. Holding a new coin also locks 0.1 ALGO, which is the network's minimum balance rule, released when you stop holding it. The approval card warns you when a trade will start holding a new coin.
When the ALGO runs low
When a trade is built, PortMula checks that the wallet it is built for has enough spendable ALGO for its fees and for any new coin's minimum balance. If it does not, the trade is refused, nothing is signed, and the build is not charged. ALGO held as minimum balance cannot be spent, so a wallet can show ALGO and still be short.
The extra ALGO from setup is spent a little at a time as your agent trades, so an active agent can need more. Send a little ALGO to your agent's address, which is on the Wallet page. A withdrawal needs spendable ALGO for its fee too, so if you are emptying the wallet, withdraw ALGO last.