There are a few pay-per-click search engines in English. Most famous are Google AdWords and Yahoo Overture. Google AdWords is not the first program but so far most comprehensive and easy to use one. Open an account with it only take you several minutes. Here is its URL:
https://adwords.google.com/select/

The minimum cost per click is $.05 to join this program. You bid for the position you want. If a keyword is highly competitive, it can cost you as high as $30 to get a click. However, this is seldom. Bid for most keyword ranges from $.10 to $.80. There is no minimum or maximum budget. You can set your own daily budget and spending will never exceed your pre-set budget. Also, you can choose to pause, stop your advertisement any time.

The second equally famous PPC campaign is provided by Overture, now purchased by Yahoo. To advertise with Overture is a little inconvenient. It probably will take two to three days for your account to become active. Overture needs real person to review your site, title, and keywords before your ads can be shown through its network.

The minimum cost per click is $.10 for this program. You can find detailed information on how to start with the following URL:
http://www.overture.com/

MSN currently does not set up its own campaign. It uses Overture paid search results.

Besides, there are other several pay per click search engines, such as FindWhat, LookSmart, Kanoodle, etc. Since they account for less than 10% traffic, we will not talk about them one by one. You can learn about details by visiting their sites.

FindWhat: http://www.findwhat.com
LookSmart: http://www.looksmart.com
Kanoodle: http://www.kanoodle.com
Ah-ha: http://www.ah-ha.com