Most shelf pulls are exactly that: items that were for sale and on display in a store, but weren't sold. These items have usually been marked down multiple times and may have had a lot of handling by customers and warehouse staff, causing some minor cosmetic damage to the item or its packaging. Shelf pulls are often included in liquidation lots and are usually highly sort after due to their good resale potential.
Many retailers find that shelf pulled items can be highly profitable. However, product sourcing experience is vital when dealing with shelf pulled items. This is simply because shelf pulled items have obviously been pulled for a reason. Most of the time this is because the items did not sell fast enough. Often, a bit of clever marketing and well written listings can help to sell the items fast when you get your hands on them. Furthermore, because online retailers have lower overhead costs than brick and mortar retailers who sell the shelf-pulled items, you can often afford to sell the items cheaper.