Advertising at price comparison sites?

Have anyone had any experience advertising at price comparison sites like www.PriceComparison.com?

They are offering free 30 days trial? They charge per click basis.
Is it worth it?

LinuxGuy

I tried your link but found it a bit difficult to find the right category for my product.

I use pay-per-click with a few different outfits, but I didn't care for the "look" of PriceComparison. Am I missing something?

best is to try a campain the free period they offer: calculate ROI
you get from them then you will now if tehy PPC rate is profitable.