can you really add wordpress theme in drupal? i am a new comer to drupal and i wish to possess a blog of mine, i am doing the work like a free and should not buy wordpress theme, so can one fit everything in in drupal as wordpress?

It's clarified around the drupal forums: http://drupal.org/node/214024

You will find lots of free wordpress styles that anybody may use, and lots of free drupal styles.

if waht you are asking is whether or not you are able to edit your personal styles, add your personal css/js, without having to pay anything upfront, the reply is yes. however, drupal isn't a hosting service like wordpress.com, you'll need your personal host (just like you'd with wordpress.org).