My theory is that people were ignoring the part that said "Only available in store," and were still trying to order it (perhaps by calling TigerDirect?) at the $99 price. At 19:50 GMT (3:50 PM EDT) I took this snapshot;notice the $99 price and that it says "Only available in store."
These went in stock for a few min @ around 12pm PST. They were for $99. I was able to get an order through. Hope i can get one. As a seasoned Webos user it'd be nice to have this tablet. Interesting to see how its future pans out