Ask HN: POS Systems w/ CC processing

I know very little about POS systems, and my parents have asked me for advice on one, produced by Intuit, that they are considering for their small retail shop (right now they are keeping inventory by hand). I'm not sure exactly what the quote they got was, but I'm quite sure it was over $1000 up front, along with some monthly fees.

Their needs are pretty simple: scan items into inventory and assign prices (cost and retail). Then to sell they would scan items to produce an order, select payment method(s), process any credit card payment by physically swiping it, log the transaction, and update inventories/sales totals/etc.

I feel that with the proper knowledge and hardware (e.g. an atom board, card reader, upc scanner, keyboard, and display), that system could be produced pretty cheaply and easily. Unfortunately, I don't currently have that knowledge, and I just started a new job that has me very busy. Does anyone have a good suggestion for a reasonable provider of POS systems? The optimal solution would also account for future expansion into web (non-POS) sales.

Secondarily, if I (or someone else) were interested in building such a system, do you have any recommendations for resources or for good POS credit card merchant/gateway/whatever (I know nothing about POS CC transactions) providers? While I was looking into building a retail website, BrainTree looked like an elegant solution to a difficult problem. Is there a similarly-simple solution to handling POS transactions?