When you receive the error message "You have insufficient gas to fund this transaction" when trying to do a transaction, it means that you don't have enough Ethereum (ETH) in your wallet to cover the cost of the transaction.
Each transaction requires a transaction fee in the form of gas that needs to be paid with Ethereum (ETH).
Solution: You need to buy Ethereum and send it to your Ethereum wallet in Metal Vault. With $10 worth of Ethereum, you're able to do a couple transactions. You can use an online USD to Ethereum Converter to find out how much $10 is worth in ETH.