shopping for scripts is difficult, because you need to be able to understand how a script works before deciding if it will do what you need correctly and -most importantly- reliably. I've never used either of the scripts you linked to, so I couldn't say. It does look like the sort of feature set you might want, but I have no idea of how well they work. It's pretty important to know something works when dealing with money.

If you're already using IPN, you should be able to set up your paypal account with passcodes - they have that feature specifically for people who sell digital downloads. It would be a lot better than just giving everyone the same code. You would still need to set up a script on your site that would check/ authenticate the code, however.


About "helping you": I'm going to answer that very carefully....

If you want to try to do this, I'd be happy to look at what you come up with and give any opinions or advice I might have.

If you want me to do it for you, please contact me and we can discuss costs and exactly what you need done.