Well, not totally free, it costs 10-15 minutes of your time :o)
I think it's worth it! Sign up with Lilaguide.com and then write just 10 simple reviews and you will receive a $5 target gift card in the mail within 4-6 weeks of writing your reviews!
click the reviews tab
type the name of the place you want to review, or just click "look it up" to be shown all results.
Lilaguide will email you when you write your first, third, sixth reviews and then when you finish your 10th, you will receive an email telling you that your target gift card is on its way!
Make sure your profile is up to date with your address so they know where to send the card!!