Lots of options out there, depending on your level of usage.
If you don't currently accept cards or if you have small volume, I'd recommend Square or GoPayment. There's no charge to get set up & they're easy to use on a smart phone or tablet. Service fees are in the 2.75% range.
For higher volumes, definitely check into your bank/credit union or a card processing company. These will generally have lower rates.
I'm a one man operation. I've used Square for a couple of years. Deposits hit my bank account no later than 2 days after I swipe the card.
As someone else replied, simply build the service charge into your overall rates. YTD, 26% of my sales have been cards. My fees are only 0.8% of sales.