Accepting credit card payments with my cell phone?

[Shane Moss]

For those that don't know, a new company called square up allows you to take credit card payments using your cell phone and a card reading device that plugs into the headphone jack. There are no monthly fees and no application to fill out. You are only charged a small transaction fee for each swipe. You can also manually input the card number into your phone, but the transaction fee is a little higher.

When I set-up my account months ago, I attached it to my personal account because I did not have rental property at the time. I didn't really need the thing, but I thought it would be cool to use for those times when you're trying to split a bill at dinner with friends. Anyway, now that I'm in the rental business, I was wondering if I should offer my tennants the ability to pay their rent plus 3.5% (the maximum fee charged by the processor) with a major credit card. My biggest concern is that they'd use it to pay for the rent that they otherwise couldn't afford. I'd hate for it to bite me in the butt later down the road when their monthly credit card payments become unmanageable and they can no longer afford rent.

What do you guys think?