I sell on Amazon, and paid-for reviews have just been killed by Amazon. They were not working.
What it does
It provides quality purchases by allowing a focus group to see the product before committing to buy it. They can feed back about the product directly to the seller, who is encouraged to video chat with the focus group. If members of the focus group like the product, they can buy it on Amazon, for the normal price, leaving a review.
How I built it
Symfony 3 Framework, Bootstrap 3, JQuery and mySQL. Running on Linux with Vagrant and eventually AWS.