Overture - Previously called Goto, Overture is the first pay per click search engine, and by far the most popular. The minimum amount that you can invest in Overture is $50.
(Note: Overture has increased its minimum bid to 5 cents and minimum monthly spend to $25.)

The largest of pay per click search engines, Overture.com has a well organized system. You can bid for rankings and also choose the description and title you want, which provides highly targeted traffic to your website. You can control your bids at all times and adjust them, based on the quality of your results. Especially handy is the Search Term Suggestion List, which shows you how often people search for a particular word or phrase.

Advertiser Tips and Tricks gives helpful tips from Overture.com's experts.

If you're in the top 10 at Overture.com, your link appears when someone searches using Dogpile meta search engine. If you're in the top six, you'll also appear in Metacrawler searches.

More people will click on your link if you use your key phrase in the title and in the description.

You'll probably receive more traffic from Overture.com than from all the other pay per click engines combined. However, because they are less popular, buying highly targeted traffic is much cheaper than at Overture.com.

The huge advantage of this kind of advertising is that you pay only when someone actually visits your site.

FindWhat

At FindWhat search engine, you bid on keywords or key phrases within search results. You pay only for click-throughs to your site. The minimum amount needed to start an account is $25.

In March 2000 FindWhat introduced new technology designed to read most simple plain English queries. You can buy search terms cheaper than at Overture.com. In May, 2000, FindWhat said that more than 10 million searches a day were being made at the search engine.

You can enter up to 1000 keywords at once. FindWhat.com reviews every keyword in their system and verifies its relevancy.


Kanoodle

Kanoodle has partnerships with sites such as, NetZero, DogPile.com, CNET, Metacrawler and Turbofind. You can choose whether you want to receive incentivized clicks to your listings or not. You can start an account with $25. Signup with our services and you will get $5 on it.


Bay9

Bay9.com boasts a high amount of traffic compared to most pay per click search engines. It is a highly relevant search engine with a referral program that pays 20%.

7Search

Services offered to advertisers include immediate e-mail notification when you are outbid for the top ranking on a keyword, a keyword generator tool, and a 1:1 banner exchange program.

Sprinks

Sprinks is not only a search engine. It is also a place to buy keywords and placement on more than 700 topic specific About.com GuideSites. About.com serves more than 500,000 searches daily on its site and will allow advertisers to name their price and control their results. Sprinks continue to work on implementing user interface enhancements.
Minimum account: $100.

GoClick.com

GoClick is a vastly improving pay per click search engine. It has received record increases in traffic and continues to upgrade the account area. It has some of the best tools available to help you manage your keywords and to help you to find more relevant terms.

Very professionally run and recommended.

ePilot

ePilot pays you for conducting a search. It also offers free use of the ePilot web portal.

Win4Win

At Win4Win you bid on relevant search terms and pay only for click-throughs to your site. Win4Win offers 2 services for listings, one is a free service and the other is a Gold Service which costs $15 to list but offers many more benefits, such as unlimited search terms and your listings are processed in 3-5 days rather than 6-8 weeks.

Win4Win looks professional and has a good setup.

SearchHound

"SearchHound will release a new search technology that completely blows away anything else on the net," the new owners say. "You'll be able to find what you're looking for faster than ever before."

SearchHound recently signed a deal with Spedia which has increased the traffic to bidders accounts.

Your bid applies to all of the word and phrase combinations you submit in a 100-character string. (The FAQ says 40 characters but the sign-up form says 100.) Not only does your bid apply to that entire phrase, but to all consecutive combinations of words found in that phrase.

Minimum account: $25.