re: Small Business owners / taking credit cards

You seem to have a decent grasp. If you are doing once in a while deals, square will work (there are others, check pricing)

Doing it thru a regular merchant account will save you at least 1%, probably more depending on the card being used.

So if those savings aren't enough to deter you, then stay with a square like product. I think there are lower flat rates than 3.5% out there.