I would always be afraid of anything offered for free. Usually it always has a catch. If it happens to be pristine then we should be thankful. Even so, we need to be very observant. We might end up paying more or signing up for other services we don't really need just to show our gratitude. One other thing that also scares me would be to be used as guinea pig. Anything could be offered for free or a very low price because it's possible they just need to get test results from us. It will be very risky.