1. Why not just use your debit card (which comes with every checking account) unless you have only a savings account)? I'm not sure which hosting takes just your routing number and account number (never really thought about it before or looked for it).

2. If you're looking to do develop something from scratch, I recommend using something else other than a cloud computing. EC2 is not cheap for development purposes. I would switch to EC2 when you need it but the costs can scale pretty high (I've been using EC2 and AWS in general for about 3 years now).