The licenses for sale on the site are all used and discarded that's why the cost is always competitive.
A Software is intended used when discontinued by a previous owner and put back on the market under the C.E. C-128/2011. Generally, these Software come from companies that have changed their systems or upgraded existing ones or that have purchased software in stock, later putting the surplus software back on the market. These products are as good as new, which makes their purchase worthwhile.
The Court of Justice of the European Union (CJEU) ruled on 3 July 2012 that the trade in used programs is legitimate and is allowed even if it is software transferred online.
" in exchange for a payment, you stipulate with the user a license agreement, by which the user himself obtains the perpetual right to use this copy, the copyright owner has sold the copy to the user and therefore exhausts his exclusive right of distribution . "
Here is the link of the press release 94/12 concerning the motivation of the sentence in the dispute C-128/2011.
http://curia.europa.eu/jcms/upload/docs/application/pdf/2012-07/cp120094it.pdf