Something to also consider with this promotion, and really any time you buy a customized jersey from Jersey City/PHL/NHL.com/etc. is the "sim-stitch" lettering that is present on some jerseys.
It's kind of hard to tell from the picture below, but basically instead of a three-layered twill, it's one layer twill with the colors and stitch graphics sublimated onto it. It's a very low-cost option that gives the appearance of a sewn, layered number. NHL.com is the worst for this, but I've seen it at a lot of places, including the FanAttic. It's sold for the same price as a properly layered and sewn jersey.
The better case scenario is that the numbers/letters are layered and sewn together, but have an adhesive on the back that can be then heat-pressed to the jersey with no sewing required.