Square, the phone dongle credit card processing people, seem to be having a promotion where they waive credit card processing fees for your first $1000 in transactions if you sign up for an account through a
referral link.
(You actually don't need to request a dongle, they let you also take transactions by directly keying in the credit card information)
If you are interesting in doing this, I would proceed with caution.
The best idea would probably be to enlist a partner in crime, charge one of their credit cards through your account and vice versa.
It's probably a bad idea to run your own credit card through your square account.
For example, my wife and I each signed up for accounts. She charged one of my credit cards that needs minimum spending, and I will charge one of hers that needs minimum spending. So far no problem. Will keep you updated if anyone is interested.
I'd put this under slightly high risk churning, so be careful out there :)