Pay per Click is an online advertising technique, which is keyword based. The advertisers place their advertisement on a website, hoping that when a customer uses some specific words to conduct a search, he will come across their advertisement and click on it. This customer may then go on to make a purchase from the website, adding to the sales volume. The advertiser in return pays the website if his add has been clicked upon. This, in short, is the gist of Pay per Click or PPC.

Thus, you pay a website or search engine for the traffic it sends your way. Google AdWords and Yahoo! Search Marketing are the top PPC players. MSN too has made its foray in the last year by launching the Beta of MSN AdCenter. Depending on the search engine, minimum prices per click start at US$0.01 and can reach up to GBP£18+. Popular search terms cost more on popular search engines.

Other than the big names mentioned above, there are hundreds of Pay Per Click Search Engines, and the number is constantly on the rise. Here is a list of top Ten PPC search engines that will help you decide where you want to buy traffic from.

1. Google AdWords - It is the largest and most popular source for traffic. Google AdWords offers unique benefits of prominent exposure, continuous variation in add format and text, and the ability to target your ads to specific geographic locations and languages.

2. Yahoo! Search Marketing - search engine marketing at Yahoo! Search Marketing helps attract more and more customers while offering flexible budgeting options, the ability to target a local audience and customers across the entire market, tools and features for easy management, and a simple five-step start-up.

3. MIVA - The key benefits of Miva Pay Per Click include total control over how much you pay for the leads you receive, instant results, and broad reach across thousands of websites. MIVA is undoubtedly one of the best!

4. Enhance - With Enhance Pay Per Click you get traffic starting at $0.03 per click, professional account management, detailed performance reports, and campaign optimization. They also have a special offer of $25 worth of Free clicks on sign up.

5. GoClick - This website has a loyal and continuously growing following as it offers quality traffic at value prices with no risk, and low $.01 minimum bids. There is no startup fee either.

6. MSN AdCenter - Microsoft Ad center is relatively new and provides Pay-per-click advertising for budgets of all sizes. It works on a simple three step process. You can get started with $5!

7. 7Search - 7Search, though smaller, assures quality website traffic. It has an interesting interface and is a name to reckon with in PPC advertising.

8. Search123 - One of the oldest PPC search engines, Search123 offers low cost per click services and high return on investment. There is no set up fees either. Enjoy the easy to use interface, and free services such as keyword optimization, 24-hour bulk loads, account management services and more!

9. SearchFeed - Strong return on investment and offers Geo-targeting with 11 countries, which can be specifically focused on.

10.ABCSearch - Offers qualified Pay-Per-Click traffic, with features such as Geo-Targeting, Bulk Upload System, No Sign-Up Fee, Advertiser Support, Daily Spend Capping, Max Bidding Feature, Detailed Keyword Trends, Strict Click Fraud Protection, and Listing Approval within 24 hours.