Paying for Hive OS is a very simple procedure. Just follow this instruction:
Apart from ETH, you can also pay for Hive OS with Stablecoins (TUSD, USDC, USDT). Please note that TUSD and USDT are not the same coins!
Remember that you can also pay for Hive OS on Hiveon Pool (3% dev fee) while mining Ethereum or Ethereum Classic. If you have more than 50 devices, you will get a discount.