If you’re a consultant or someone who’s constantly mobile for your business, having a way to charge a credit card on the fly is very helpful. Yes, you can use PayPal for credit card transactions, but if you need to swipe a card fast, and you’re out of the office network, you need a more accessible way. This can pertain to computer consultants, advertisers at trade shows, home repair folks, doggy walkers, you name it. 
Here are the top 3 iPhone mobile credit card apps:
- Mophie – Although it’s $80 upfront for the reader, it’s the only one that integrates easily with Intuit QuickBooks for easy data exports. It costs 1.7-2.7% + 30 cents per transaction.
- Square – This free reader is a very user-friendly app. It takes 2.75% per transaction which is a bit steep, but this is an ideal tech solution for lots of credit card charges.
- PayAnywhere – This free reader is very reliable with a quick connection to its server. Unfortunately, it only
works on the older iPhone 3G / 3GS (does not support iPhone 4) and takes a hefty 2.69-3.49% + 19 cent-transaction fee.
If you already use some form of QuickBooks, Mophie is recommended due to its easy integration with the accounting program. Otherwise, it’s a matter of which app interface you’re comfortable with since they all perform the same thing: charging credit cards wherever, whenever.