There is a condom distributor, "Condomman", that sells on Amazon.com, that buys Durex condoms in bulk from the company and then breaks bulk to sell them to customers through Amazon. Since the condoms that he sells do not come in small boxes like 12 or 36 packs like condoms you would buy at the supermarket, he can offer them at a deep discount. In this screen shot of Amazon, you can see that the 12 condoms MSRP is $9.99, yet Condomman sells them from $0.89.
Condomman's prices are so low because he is the only middle man in the supply chain. Further, there is less packaging which also creates a savings.