Here is a link to more information on the Staples web site: http://www.staples.com/NCR-Silver-POS-Cash-Register-System-for-iPad/product_100599
Of note, offering point of sale solutions through office supply stores is not something new - Intuit offered their QuickBooks Point of Sale bundles through office supply stores for several years.
The $499 price point is great but keep in mind that you still need to pay the monthly NCR Silver fee after the 30 free trial period (currently at $79/month or a total cost of $4740 over 5 years - yikes!). An iPad is not included, nor is a barcode scanner or customer pole display. You also can't print barcode labels/shelf tags using NCR Silver.
If you truly can't afford to invest in a point of sale system (or obtain leasing/funding for a system), then NCR Silver is a viable option to a cash register. Just keep in mind that you will likely end up spending $6000 - $7000 on NCR Silver over the course of 5 years. For comparison, a complete Windows-based point of sale system would have a 5 year cost starting around $4000-$6000.
I have some comparison charts showing what Silver can and can't do compared to a true point of sale system.
Are you in the US and in need of no cost retail point of sale advice? I'm happy to help and can be reached on my cell at 208-340-5632 (mountain time) or via email at firstname.lastname@example.org.