I wood like to pay 50GB for 1 year?

Welcome to the Apple Community.

Sorry, it's monthly payments only.

The annual plans were discontinued years ago now. There are only monthly subscriptions for iCloud storage now.

The only other option you have is to purchase and redeem an iTunes or App Store gift card with enough funds for at least a year. The gift card will be charged monthly before any other means of payment.

Redeem App Store & iTunes Gift Cards and content codes - Apple Support

Well, they are discontinued in that Apple no longer offers them. That to me is the definition of a discontinued service. One no longer offered to new customers. But, not worth arguing over semantics.

Indeed it's not, although my purpose wasn't to argue with you, I was just adding another post with unnecessary information that the OP probably didn't need to know.

The plans weren't discontinued, they were just not offered to new subscribers, those who have continued their plans unchanged are still paying annually.