E S.

Freeshipping.com works exactly as advertised. If (and that's a big IF) you understand the monthly fee structure and read the terms then you will know what you are signing up for and it is unlikely that their service leaves you unsatisfied. They are responsive, and run a trustworthy business which is worth it for those who do online shopping a few times at month and are willing to spend a few minutes to find the best deal (which is not always the Amazon.com even if you have free prime shipping).
That being said, they don't do a good job in helping you understand the monthly fee, and terms of service. The pop-up that they use to acquire customers at several third party websites, should show in large fonts and in several steps that this is a monthly service for which the customer will be charges $12.97 unless they cancel within trial period. And for the first time users they should let them submit the documents for shipping rebate up to several months after purchase, because many customers don't know how Freeshipping works and it may take time for them to find out they need to pay for the shipping at the time of purchase but can submit documents after the purchase to get a shipping rebate.