Any entry fee to use adsense?

No,Participation in adsense is free.

what languages support by adsense..

English,Arabic,Chinese,..etc.,around above 30 languages.

How much does adsense cost

Participation in adsense is free.even better,google will pay you for clicks or impressions on the google.

Adsense for search offers

Adsense for search offers the following :
Choosing the content your users search.
Customization of look and feel.
Monetization of search resut pages with targeted ads.

Adsense for search

Adsense for search is a free solution that allows publishers to place a search box on their site and earn revenue from relevant ads on the search results page.

Adsense for Content

Google adsense is a fast and easy for website publishers of all sizes to display relevant,unobtrusive Google ads on their websites content pages and earn money.