This happens all the time at my local supermarket. Pure cranberry juice on sale (I use quite a bit of this), only one bottle left on the shelf. Of course, once the sale is over the shelves are full. The same is true at REI. Generally, if you don't get there the first day of the sale, forget it, unless the item is not a popular one.

Why? The reason for the sale in the first place was to get rid of overstock, or of discontinued models. Once those are gone, no business will continue offering the sale price.

Not dishonest at all, just standard business practice. No firm is in business to give things away unless there is a compelling reason to get them off the shelves.