What is the best or easiest way to set it up so that customers have to pay to make a download?

Answer 1

Have ya tried setting up a PayPal account?

Answer 2

The price of a download of most stuff these days is pretty cheap, so you probably want to have each customer have an account which is loaded from a credit card when depleted. Your software will thus need the following features:
- A new customer can set up a unique ID and password. The software checks for uniqueness.
- The software solicits a credit card number, and validates it. Check with your bank to see how to do this.
- The customer will want to see a menu of selections available for downloading, if you have more than one.
- The customer will specify what he wants, and either his account will be charged appropriately, or the tariff will generate a credit card charge.
- You will need to have a FTP facility to provide the material to the customer.
- You will need to have a Help facility by which customers can contact you to beef about problems. (Essential!)
- The software must run encrypted any time that sensitive data (e.g.m, credit card numbers) is being passed.
All in all, it's a lot of work. Various vendors have already addressed all these issues, so shop around and you may find something that you can buy that is a lot cheaper than anything you could build yourself.

Answer 3

Are you renting PCs by the hour?

I did this some years ago and did not have to pay for downloads, just for the time used.