Ethereum has higher gas fees. This means that in order to mint your space on Ethereum, you will be prompted to pay a fee in order to do so. The amount varies greatly, from $25-30 (Feb 2022) up to $300-$500 (October 2021) per transaction. Unfortunately, this is the norm for minting on Ethereum, for any platform right now. The gas fees fluctuate wildly throughout the day, so if you're seeing high fees now, you can check back an hour later or even in another few minutes and you might see them a bit lower (or higher).