I want to build a recommender for my e-commerce service.
The main problem is that every item in the system is unique, and can be bought only once (so this item should be not recommended to anyone after the sale).
Service is similar to the eBay, where each item is unique, and, despite the fact that seller can publish the same item again, it will be considered as a new item in the system.
Also, there are not much common information between each item (the most common is the seller ID and the category ID), so I can not easily find similar items based on what user had purchased before.
What techniques can I use in this situation?