Before attempting to make a purchase, it is a good idea to deposit your GAME balance from the Ethereum mainnet to the Polygon/Matic sidechain. Scroll down the home page and a section with your balances is visible. Click “Deposit” on the mainnet balance to deposit it to the sidechain. This will incur an Ethereum gas fee. If you do not deposit to the sidechain before making a purchase, you will be prompted to do so during the purchase process.