I am a windows guy as well, in order to use Square you have to be online. I have square and an ipad, I still need to buy the compatible receipt printer and drawer. There is a thread here on this already, I remember replying to this question awhile ago but my search is wonky.
I have a mobile broadband card that I can use for my network connection so the iPAD will be online. If you do not want to provide credit card then just buy a plain old school register with the buttons that can be labeled. There are several POS options but most are too expensive or have a monthly fee. Square register is the best as far as cost.
Sprint is my provider and I pay $50mo for my broadband card which is a Sierra Wireless AirCard 802S, this is like a mobile router and lets you connect 5 devices all at once.