I started accepting credit cards three years ago. And even then it's only once and awhile. Mainly from homeowners. I use Quickbooks online for all my financials. They (Intuit the makers of quickbooks) offered to set me up with a merchant account for free and without the customary monthly fees, annual fee, per transaction fees and whatnot that most of the other merchant account places wanted to charge. Since my invoicing is done through email and online it made sense to allow credit card payments when paying online. I'm charged the a customary 2.7% per transaction for the service and that's the only fee I pay. Despite what other have said, it is illegal to charge a surcharge for paying with by credit card. That is a violation of the merchant member account agreement with the member cards such as Master Card, VISA, and Discover. It is also a violation of the same agreement to say you have to spend a certain minimum amount in order to use the credit. A number of donut shops here locally have signs by the register that say something like '$3.00 minimum purchase to use credit cards'. If that was reported to the card providers that merchant account would be closed. Having said all that it is NOT illegal or a violation of the agreement to offer a discount for paying by cash. Gas stations do this along the interstate.
Some merchant account providers charge something like $0.25 per transaction plus the percentage but that's getting rarer.
One cool thing was I sent a credit card reader that plugs into the headphone jack on my smartphone. One common one is 'Square' that is sold locally at Staples. But if I'm with a client and they want to just pay right then which has happened more often than I thought it would, I simply plug that guy in, pull up the invoice in the app, swipe, they sign via their finger on the screen and it instantly pays me and emails them a receipt.
The wonders of technology never cease.
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Gordon McKenzie Assoc. AIA
Tartan CAD Services
Lewisville TX
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