Automatic send a text string once paid?

[yeti1337]

I was wondering if it would be possible to:
Once the customer orders the subscription through my vBulletin, then they will receive the code via email or in the forum PM Box.

And i can set up a list of codes and it will send the top 1, then delete it or go to the next one however for the next customer (to avoid a customer getting another customer code)

Any ideas, or is there anyway i could do this?

Is there a way to do this outside of vbulletin if not with vbulletin then?