Amazon Terms Of Service
We take Amazon's TOS very seriously and, due to the new policy change with respect to reviews for discounted products, we no longer require or ask for reviews in exchange for discounted products.
In addition, we do not permit reviews, or votes on the helpfulness of reviews that are posted, in exchange for compensation of any kind. That includes payment (whether in the form of money or gift certificates), bonus content, entry to a contest or sweepstakes, discounts on future purchases, extra product (buy one, get one), or other gifts.
As we learn more about the change to Amazon's Reviewing Guidelines, we will update our own policies so that they stay in line with Amazon's Terms of Service.
Here are Amazon's TOS from their website as well, in case you wanted to have a look: