comparison shopping - best search engines?

I’m looking for shoes online for the first time and it’s a confusing mess for me. I know what brand I want, but I can’t seem to find one search engine that will show me the best prices from all the sites available. Yahoo seems the best so far and I’m surprised that Froogle is user unfriendly and doesn’t cover many sites.

In general, is there a reliable comparison shopping search engine for common consumer products like clothing, shoes, or electronics that will cover most all sites on the web?

I’m suprised to find that shoes on the web are more expensive than in the stores - which is what prompts my posting here.

Pricegrabber works best for me.
Follow that with Froogle.
Froogle is very pretty, but when I was looking for the weird shoes I wanted, Pricegrabber delivered. Froogle delivered, but it consistently delivered higher prices.

Thanks! I forgot to mention I want new shoes. Froogle gave me used shoes too, from ebay. Yuck.

Heh.
I will say, there ARE some Ebay sellers who are actually selling legitimately new goods.