What  is a pay per click search engine?
From a surfers point of view it is the same as a normal search engine, except that the results are business and product related.

From an webmasters point of view it is an excellent way to get cheap targeted pre qualified traffic.

A pay per click search engine enables you to open an account and deposit  money as a starting balance. With this, you enter your site's URL, title and description and bid on relevant keywords. A site selling SEO Products would bid on keywords such as, "SEO," "SEO Ebooks," " SEO Software" etc.

When someone searches for "SEO Products" the details of your site appear, in the form of a search result with the URL, title and description you entered. If they then click on your listing, your account is debited the amount you have bid on that keyword.

What is exceptionalally good about this is-If they searched your Keyword or phrase-then clicked to your site-there is more than a good chance that they are  intrested in your product.

Before you pay for any adds or PPC, Pay for Placement search for your site: Ensure the site is loaded with goodies for them to buy, working smoothly and functional. If you don't it is money down the drain.

Here are a few to try:

http://www.askalex.co.uk/ (UK BIASED)

http://www.mamma.com/

http://www.searchup.com/

http://www.thenet1.com/