Crypto Payment

Hi guys, this is gonna be my first order and I've decided to pay with crypto. However, in the checkout, the total amount is more than the order amount (for instance, with solana, the website gives me 0.99 solana, which is almost 150 GBP while my order is 110 GBP. What's the reason of that? (I'm not using Royal Mail delivery so there's no addition).

Many thanks in advance for your responses.