No, people will not want to sign up, site-by-site. No they will not want to use 5 different billing systems. But make it affordable and put in on the ISP or phone bill and give them no other choice and watch what happens.
It has long seemed to me that sellingf content for less than a dollar is the way to go for (at least serious content) publications and the $10 deposit solves the transaction cost problem with the credit card companies (and provides a very nice working capital source at the same time, the float earning interest if banked).