Discount on number of items not time

[Weasel]

The ability to give a discount on x items instead of a certain time?

Reasoning: I buy items from suppliers at a fixed prices but sometimes I get a certain quantity of the same item from a liquidation or somehow else reduced.

I would like to pass these savings on to my customers, but that discount would only apply to x out of y inventory.

If I set a timed discount I might loose out since I could sell substantially more items than the quantity I got at a special price.

Setting up a new item just for a discount isn't a solution either.

I made a feature request, if you like the idea support it please:

http://www.prestashop.com/bug_tracker/view/2532/