No strings attached! A while ago I became an Allure Expert. The rundown is that certain companies like Chanel will send you a new product to try either before they go on the market or as they are launching. Your only obligation is to use it and give them feedback. I try not to think about the human guinea pig perspective and say "Don't look a gift horse in the mouth."
All you have to do is sign up at Allure Experts. It's free stuff and no coupon clipping.