I did the first one with paypal a couple of weeks ago.
It's about a 3% charge. Higher than most others but I don't see having to use it more than a couple of times per year. With most companies you have to use it quite often to get a discount or pay a service fee.
I just add the charge to the bill and make the customer aware of it before doing the work. The customer was ok with it.
For a $1600 job it was about $50.
With paypal you can email (I think there are other ways too) the customer an invoice and do not have to have a card machine.