Hi, I'm trying to put together a site like a shopping cart. The difference is users are redeeming points they have earned not money. Sort of like SkyMiles. My question is, does anybody have any ideas on how to do this? I have a database that has their user points. I just don't know how to execute a function or behavior that would first, check the total points required - second, check the available points the user currently has - and third, write that to the database. Any help would be very helpful. Thanks!

chris