Gas fee

A gas fee is what you pay the network to process and record your transaction. You pay it in the chain's native coin, such as ETH on Ethereum and Base, BNB on BNB Chain, or SOL on Solana. The fee goes to the validators who include your transaction in a block, not to the app or the token's team, and on some chains part of it is burned.

On EVM chains, the fee is the amount of computation your transaction uses multiplied by the price per unit, quoted in gwei. A plain transfer needs little computation, while a swap or a contract interaction needs much more. The price per unit rises when many people compete for limited block space, so the same action can cost far more at a busy moment. Since Ethereum's London upgrade, that price is a protocol-set base fee plus an optional tip that buys priority.

Solana works differently, with a very small base fee and an optional priority fee. Layer 2 networks like Base are cheaper because they batch many transactions together before settling on Ethereum. Cheap does not mean free, though, and you still need the native coin to pay.

This matters because you cannot do anything without that coin. A common beginner trap is a wallet holding a token worth real money but zero native coin, which means you cannot sell, move, or even revoke an approval until you top up. Fees also weigh heavily on small trades, since a flat cost of a few dollars is a large share of a twenty-dollar buy.

Failed transactions still cost gas, because the network did the work before the transaction reverted. This happens often when slippage is set too tight on a volatile token, or when a contract blocks the sale. Before signing, confirm you are on the right network, read the fee estimate, and be wary of manually setting extreme fees. If a token's sell transaction shows an unusually high gas estimate or fails in simulation, treat that as a warning sign and look at the contract before buying more.