In the case of things that have recurring payments, I think a lot of places don't like prepaid cards because they tend to run out of funds fairly quickly and never get recharged again. And especially for things that have a free trial, they want to know that they can charge the card as soon as you forget to cancel the trial before it ends. Perhaps they also don't like the anonymous factor - you could claim to be anyone when using a prepaid card.
There also used to be a problem where people would use empty prepaid cards in machines that didn't immediately "dial out" for a credit card authorization, such as some vending machines. The machine would just trust that they could charge your card, until it called out a batch of authorizations at the end of the day. Now I think a lot of those are programmed to auto-decline prepaid card numbers.
Total Loan Balance: $43k / $65k
Total SL: $78kIf you have Citi or Capital One cards, you could try using the virtual account number feature to generate a credit card number that isn't tied to your account information. The added bonus is you can close the virtual account number (say, if someone keeps trying to charge your card and you don't want them to) without having to close your actual account. Other banks may offer that as well, I'm only familiar with Citi and Cap1.