Where can I join the contests and promotions for book?

You can find that information here:

Rules & Conditions regarding our Promotions and Giveaways*

1. Contests are divided into those requiring a purchase and those which do not. Those which require a normal purchase do not affect or change the price of our products.

2. Each contest requires that the entrant be truthful and accurate regarding the information submitted.

3. All entrants are subscribed to our general newsletter at our site and our taalib.com groups or our contacts lists hosted by third party companies such as Twitter or Facebook, only for the taalib.com website.

4. Winners have (3) three days to respond with information needed to transfer any prizes. When no response is received in that time a secondary winner will be chosen in their place.

 *All taalib.com giveaways comply with the guidelines of the Sharee’ah. Our basic guidelines are  based upon what was mentioned by the guiding scholar Sheikh al-‘Utheimeen, may Allaah have mercy upon him, of conditions and guidelines for business contests in several different questions from his “Open Door Gathering” recordings.