The offer for 1244.- is from the retailer "Das Warenhaus" and not from Digitec itself. If you study the product page more closely, you will notice that. In addition, Digitec does not currently have a lens in stock, "Das Warenhaus" thinks they do, which is why they charge a higher price.
2) The reference to showroom does not mean that it is a used lens. It means that it is on display in one or more Digitec shops for you to look at. If you buy it, you get a new lens.