Transacting on Ethereum incurs costs, fees paid in Ether to the ‘miners’ that ensure network safety.
These fees are called gas, and like gas for your car, this gas is the computational fuel required to get your transaction to its destination.
Each transaction sent on Ethereum has both a gas limit, a total amount of gas required to complete your transaction, like fuel to get your car from point A to point B, as well as a gas price, essentially the price per gallon of that fuel.
As a general rule, a user cannot ‘overpay’ for the gas limit, only the amount of fuel necessary to complete the transaction should ever be consumed.
Gas prices, however, are highly variable and users can easily over or under-pay by adjusting the gas price prior to submitting their transaction.
A highly-priced transaction will generally go to the front of the line, while a low-priced transaction will simply wait in line, ‘pending’, until gas prices go low enough for the transaction to be accepted.
Gas prices are always fluctuating, and at busier times the costs can spike dramatically.
We aim to keep our contracts as gas-efficient as possible, but we have no control over the gas costs during periods of high network activity.
Most wallets, like Metamask and Torus, offer suggested fee prices based on current network activity but ultimately the decision on what fee to choose is in your hands.