This one is easy: blow out offers on selected products for a limited time of 1 week.

Most of the times it will be just one unit of each product so they will be sold strictly on a "first come, first served" basis.
If the item has not been sold at the end of the week, it will return to its normal price and the offer price won't apply.

In those cases where we have more than one unit of the product, they will get sold until we've run out of them.