This question is actually for the fixya team can someone tell me how is it possible that a fixya member can ask unlimited questions for one month if he has paid 9.99$ / month member ship whereas on otherhand with other time of membership he pays about 12$ for one time email support ? is there a catch or have i misunderstood something ?

You have understood well.
Paying $9.99 you can ask unlimited question to the vast crowd of selected Fixya experts.
Paying $12 you will ask only a single question, but your question will be passed first only to Fixya Top expert.
If the problem is simple, or if you have several questions on different topics, better to purchase the Fixya Unlimited subscription.
If you think that your problem is of more difficult resolution, then better to purchase the $12 single shot question.
Top experts occasionally can also answer the $9.99 questions, but have priority only on $12 ones.
Hope this clarified your concerns.
Thanks for asking us and goodbye.
Ginko.