I cannot recommend any particular one – they all, in my opinion, should be imprisoned for usury.
Rates will vary considerably depending upon your volume of transactions, but a lot have “hidden” charges, e.g. the percentage (2 – 3-/12%) <u>plus</u> a fixed transaction fee (like 10 – 15¢) <u>plus</u> a monthly “maintenance” fee (like 10.00 – $15.00). They all add up in a hurry.
You can either buy or lease a terminal. Do the arithmetic. In the long run it is cheaper to buy, but you won’t get service (but I have never had any problems with mine).
For years I have resisted buying or renting a printer. I still emboss the triplicate strip. I’m saving a few bucks per month that way.
Once you get established, other merchant service companies will come out of the woodwork and get you to switch. At that point, the pricing will get really competitive.