Paid Reviews are an excellent link building method. You just paid a website to write and publish a review of your product or site, including a link to it (usually with your keyword as anchor text).
You should also check whether people are looking for review of that specific product for which you are paying. If people don't care about reading reviews of those products, you money would get wasted instead you can spend those money in real link building activities like buying premium account in article directory for more exposure or buying blog post.
I agreed,
Paid Reviews are commonly used way to get backlinks.