What fees are involved when transacting with Web3?

The only fees related to the Bitso Web3 Wallet are the standard crypto withdrawal fees when you send funds from the standard custodial wallet to the Bitso Web3 Wallet. Aside from that, all the other fees associated with this product are related to Network fees.

What is the Gas fee?

Gas is a measure of the computational power required to execute specific transactions on the Ethereum Main Network. 

Since each Ethereum transaction requires computational resources to execute, each transaction requires a fee. Gas has a price in ETH, and that price depends on the network capacity at the time of the transaction.