Sprint is going to start selling the 16 GB Wi-Fi only version of the Galaxy Tab 10.1. This is a strange, but not unprecedented thing for a carrier to do. Verizon did the same with the original iPad, but they bundled a hotspot with it. Sprint is evidently not going to be bundling a hotspot with it, but instead pushing it when they sell you the Tab outright for $499.
It will only be available online through Sprint at first, but starting July 24th it will be available in Sprint retail stores as well. If nothing else, Sprint will be another place you can pick up your Wi-Fi only Galaxy Tab 10.1 if your local Best Buy is sold out.