Are you going to be dealing with tens of thousands of coupons?

I didn't think so, so why bother using a database with Access and mess about with all the setting up when you can create your own simple textfile with the information you require. You don't even need to have the kiosk directly connected to you, it could get the textfile from a location online and you upload it there (or FTP it over to the kiosk if you run a prog to do that...personally I suggest HFS which is actually a HTTP file server with uploading capabilities).

You don't need to use a sledgehammer to crack open a walnut :-P