How does click-through income work?

[Clodfobble]

Well here's how that site suggests they should get paid.

Does it cost to get my products listed?
Kelkoo only charges you when a user clicks through to your site after choosing one of your offered listings. Each category has a different minimum cost.

Your offers and shop will appear more prominently depending on popularity, relevancy and the price you pay.

How do I get my products listed?

--Product feed upload
For free we will help you produce a file, in a specific format, that can be updated and uploaded each night.

--Kelkoo Spider
For a fee we can scan your site and collect your offers, then list them on Kelkoo*.