I've never seen this model go on sale. More surprising to me is that the price hasn't gone up since it was introduced. Shipping went up $10 , but I can't fault HSU for passing along an increased cost.
They do have a "B-stock" page, listed about 3/4 down on the FAQ page, but I've never seen an VTF15 there...and there's not usually much there at all. AFAIK, it's what they do with returns from their 30 day in home trial offer...and those items don't offer returns or an in-home trial. Really, there's hardly ever anything there, and when something does pop up.... 10 to 15% off ... it's not there long.
I'd say just get it if you want it. That sub wouldn't be less capable even ... not on sale.