In my business, we had a lot of small charges ($10 for a propane cylinder refill at that time) and a few big ones each month (folks buying really expensive stainless steel grills). I pretty much had to have credit card services; most people expected it. Like the others, I paid a monthly statement fee (around $25), a transaction fee (started around 10 cents, went close to 15 cents), and a percentage of each sale -- around 2.2%. I went to my bank and asked who they liked for a processing company, and they arranged to have the CC gal come to my store and get everything set up. I did not have internet CC per se; I had internet sales, but folks called me with the CC number. Internet processing is a whole different ball of wax; at that time companies were a little leery of it; I expect that they've gotten a lot more comfortable with it in the past 10 years.
I did not lease or buy any specialized equipment except a card swiper attachment for my computer. It went inline with my keyboard, and when I swiped a card through the magnetic reader slot, the information was sent to my computer as if I had punch the keys. I had a bar code reader that worked the same way (my keyboard cord had a couple of "Y" adaptors). I used a program called Regit that is a Point of Sale system. Kind of a simplified system that requires you to have a bit of computer knowledge to interface with QuickBooks. It had a CC module that automatically dialed the CC company and got an approval for the swiped card, just like the big boys at Wally World, etc. The program also interfaced with a cash drawer and a receipt printer. The best part was that the whole thing, hardware (drawer, printer, CC reader, bar code reader) and software (POS system and CC module) was less than $1200, plus the cost of the computer, but the system was happy with an older machine with only 64K memory; today that would almost be the least expensive comonent. The program also networked to the 'back room' where I had another computer where I did purchasing, inventory control, etc. It was a slick setup. They've lowered the price; I think you couild put the whole thing together for about $600 or $700, now.
Regit Point of Sale - you can download the software and play with it.
I still have my setup and could be persuaded to sell it, but it wouldn't be overnight -- Some of it is in storage and I'd have to dig it out. There are some upgrades -- I think you'd be as well off to buy new.
As far as the cost of the CC processing, I just thought of it as a business expense like electricity or trash service. While I did account for it as cost of sales, I didn't try to work it into the price of the item. The best way to accept a credit card is to not worry about how much less you're making on that sale, because it's likely you wouldn't have made the sale without the card. It WILL increase your sales.