As described on the Gas page, the Ethereum gas block limit means that there is a limit to how many computations can occur per block. This creates a fee market for gas where miners will accept higher paying transactions first. Users that want their transactions to be included first can pay a higher gas price than those who aren't in a rush. Key concepts to understand about the fee market are:
| Term | Description |
|---|---|
| Gas Price | How much a user is willing to pay per gas for work (in gwei) |
| Safe Low | A price that will be mined in a reasonable time (<50 blocks) |
| Standard Gas Price | The average gas price being paid by the network |
| Fast Gas Price | A price that will be mined within the next few blocks |
The best resource for the Ethereum fee market is EthGasStation.