online payment verification

[phppup]

I'm trying to create a series of web pages that will lead to a FINAL SALE page.  At that point, I require TWO things to happen. First, the customer must pay the displayed total. Second, some kind of automated receipt needs to be generated so that a script can allow the customer to progress further.

An applicable example would be a customer navigating through web pages of paintings by different artists and then choosing to see Alfred's latest unreleased paintings for a $2 fee.  After paying the $2, the next web page would validate receipt of the payment, and now allow the customer to access Alfred's gallery.

Is there a template for this sort of thing?

Obviously, an online payment would require a credit card.  Any recommendations for service providers would be appreciated.

I have contacted Pay Pal, but they seem trained to encourage Ebay type sales and insist that the email I receive as confirmation would be sufficient.  However, that would require me to check my email and manually grant access to galleries without ever sleeping. LOL.

I'm sure there is a more viable solution, but need some advice and guidance from those that have already traversed this obstacle.

[requinix]

If you process credit cards then you can find out whether the charge was successful immediately. No problem. Some other payment methods are instant like that.

For payment methods that are not instant then you need to tap into some mechanism where they notify your site of a change. For example, PayPal has IPN which pings your site when activity happens with a transaction. You thank the user for the payment and then wait for the IPN message that confirms the payment happened - it typically happens within seconds - before you give the user access.