Gas fees and POL

A short answer for the curious: gas on Polygon is cheap, around a cent per transaction at typical prices, and 4rho keeps it out of your way.

What is gas?

Every blockchain transaction has a small fee that pays the network validators. On Polygon, that fee is paid in POL (formerly MATIC). A typical 4rho action — placing or cancelling an order, claiming winnings — costs less than a cent in gas at current prices.

You only pay gas for transactions that actually touch the chain. Sub-cent order placement happens off-chain via signed messages; gas is paid only when the trade settles or you redeem winnings.

Why most users don't think about it

The 4rho operator wallet pays gas for trade settlement and resolution on your behalf. The cost is built into the standard taker fee, not a separate line item. So most days you don't need POL at all.

Where you do need POL:

• Self-custody actions you initiate from your wallet — like sending USDC from your address to somewhere else. Those transactions are signed and submitted by your wallet, so your wallet pays.
• Cancelling an order on-chain if the off-chain cancel path fails. This is rare; the normal cancel flow doesn't require gas.

How to top up POL

Two paths:

• Inside 4rho — the wallet menu has a small swap UI when your POL balance is low. It swaps a few dollars of USDC into POL on-chain.
• Outside 4rho — buy POL from any exchange that supports the Polygon network and send it to your address.

A few dollars of POL covers months of typical trading.

"Insufficient gas" errors

If you see this, your wallet is trying to send a transaction but doesn't have enough POL. Top up POL using one of the methods above and retry. See Insufficient gas for the step-by-step fix.