Gas is the fee required to perform a transaction or execute a contract on the Ethereum blockchain. Gas is given to validators as payment for the supplies needed to complete transactions. Supply, demand, and network capacity at the moment of the transaction all affect the gas' actual price.
The “gas limit” is the most work you anticipate a validator will complete on a given transaction. A larger gas limit typically indicates that the user anticipates the transaction to be more labor-intensive. The cost per completed unit of work is known as the “gas price.” In many transactions, gratuities are also included in the gas price. The more, the better. The smaller a user's estimated gas reserve, the lower priority they will have in the queue.