The monthly payment system seems to work like this. Instead of making an immedialte payment with your credit card, or through Paypal, you can arrange to have a monthly automatic withdrawal set up with your bank. You will be invoiced for all transactions done in a month and your account will be debited 10 to 14 days after you have received the invoice. This is not a system where you can make payments over 6 months or a year like a loan.