There are several Commercial Cash Registers available with Free Polling and Programming software. What is Polling and Programming Software you ask? Well Polling means that you can take reports from your cash register on your computer. So you Poll it! Programming is just what it sounds like, you can program the cash register with the software on your computer.
More often then not it is more trouble then it is worth to connect and use UNLESS you have lots of PLU's or UPC to program into the machine. In that case the software can save you hours of time programming. And one of the packgages allows you to import items which again can save you hours and hours!
Check out the following cash Registers that Integrate to a PC for Free
SAM4s ER-265 Cash Register with FREE Software
SAM4s ER-285 Cash Register with FREE Software
SAM4s ER-390 Cash Register with FREE Software
Sharp ER-A242 Cash Register With Free Software