Knee sliders are a tough product to do group buys on because they are a "specialty" product that the companies that make them charge a ridiculous amount to us retailers. It's just one of those products that as a retailer you choose to offer as a convenience, not to make money on. That is why most retailers charge retail for knee pucks...because they didn't pay much less than retail to get them in their store.
If you guys don't get hooked up on your group buy through the other forum, we carry a pretty cool group of knee sliders by pro-slide. All of our customers really seem to like them. There are a few different styles and lots of color choices (and they just got those new spark sliders for those who want a little more bling factor with their pucks). We sell them for a little less than retail already, so I really can't discount them, but I could offer free shipping on the pucks. Depending on where you live, that would save you anywhere from $6.00 to $9.00. Just a thought if the other deal doesn't come through for you guys and gals.