Add-on Credits 20usd for 1,000 credit (I think it too wired)

possible to make add-on credit 20usd get 2,000 credit too, Now I’m on 60usd per/month and have some additional use some time, switch to 200 usd is too much for me,

1st is it possible to have 100 usd plan
2nd is it possible to add-on credit 20usd get 2,000 credit too like subscription plan

thank you for your good code editor and hard work