Purchasing NFTs involves gas fees. Indeed, the Ethereum network requires gas to execute transactions. When you send tokens, interact with a contract, send ETH, or do anything else on the blockchain, you must pay for that computation. Refer to https://metamask.io/1559 for details. To avoid any issue during the purchasing process, please add 0.02-0.05 ETH to cover gas fees. So the mint requires 0.088 ETH + 0.02-0.05 ETH.