Selling a non-tangible product

This may be a way off the beaten path type of question, but...

Many of my products (data) are sold on the basis of having an actual hit on a particular search. My items are both instant searches as well as manual searches. On the instant searches, I would have to have a way so that the customer does not see the data until payment is made.

I was thinking it would work in a very similar way to downloading, except that the database is not pre-populated with the product (books, music, etc or in my case - search results. When the customer places the order, the system gateways through several data warehouses, performs calculations on the aggregated data and presents it to the customer. I need a control that prevents the customer from seeing the data until they have paid.

The links (although no where near completion) is https://www.infodatausa.com. Your suggestions are greatly appreciated.