I signed up for the 30 day silver membership for $4.95. I just re-signed for 90 days for $39.95. Not only have I gotten signed up with dozens of mystery shop companies through their posts, but I've also gotten a demo job for $15/hr, 12 hours per week (Fri/Sat/Sun 4-8 pm), handing out flyers and demoing a dvd kiosk in a grocery store, plus I've gotten in with 4 merchandising companies. Definitely worth the money. I rarely go to their web site, just respond to their emails.
I performed my first shop on 1/17/2007. As of today, 2/23, I have completed 68 shops and grossed over $1000.
FYI: a great way to keep track of your passwords and the companies with whom you've registered... Get RoboForm. If you earned less than $20,000 in 2006 it's only $19.95, but you can try it out for free. Go to downloads.com