The refer-a-friend program works in that the referring person gets $10 for referring a new user. Here is my TripAlertz sign-up link. The new user only has to sign up with an e-mail address, nothing else, no purchase required. However, the new user does not get a bonus. So while you don’t get a bonus right away, joining quickly means you get $10 from any of your friends that sign up with just an e-mail address. Literally just takes seconds. If you get 47 people to sign-up, you could get the 3-night Aruba package on the home page for free.
Update 10/14: Looks like they changed it to just $1 per referral. Oh well.