AlienCamel, the email service that does a pretty good job of keeping out spam and viruses I’ve mentioned in the past, is offering a year’s Clean Email in return for feedback:
We are looking for 50 special users who are willing to give us some feedback about our email service from time to time. In return, we will give you a year’s subscription to AlienCamel’s “Clean Email” service for free.
You must sign up, however, which means having a PayPal account.