Let's say I want to make a search engine that will find all the Romero Britto "Blue Dog" sculptures for sale and list them like a price comparison search engine. How would that work and who would I hire to make it happen? Obviously it wouldn't be just that on sculpture. There would be another page for his "Tiny Temptaions", another page for another work, etc. But on each page I would need a list of sites that were selling the product.
From my experience, comparison engines get a feed from companies who want to advertise their products on the engines page and it works off a PPC system. I know shopping.com works that way. You upload a feed with everything you sell, pricing, description, etc... and they charge you every time someone clicks on your link to go to your site. It's much cheaper that Google PPC. Most of my clicks are .30-.40 cents.
So you first need a network of advertisers? You can't just search their products somehow - they have to tell you which products are available?
that would be the normal way. you might try to find a programmer to make a custom script but be prepared to spend a lot of money on it. I have tried to find a good script "out of the box" and haven't found anything decent below $700 and even that script wasn't totally what i wanted.
Hiring a programmer can be tricky. Haven't found one who wasn't a flake. Even ones with good reputations on DP either abandon a project half way through or miss deadlines by a month or more...
Well, I use shopping.com and if your product isn't listed in their database, I'm 90% sure it makes a product listing for you. It doesn't have to be a pre-set product that they already have on their site. You can make the feed in many different ways from finding an addon for your shopping cart software to finding the format the feed has to be in a manually doing it yourself.