https://www.08liter.com/try -register for 0.8L and fill out your profile. Then go here and apply for their free product tests for a chance to be selected. They have new offers frequently, and with a lot of people applying for a limited spots, it might take a while to get accepted for some. You do have to submit a review after receiving your product as well. They also have product tests that involve a cost, but you can skip those if you’re not interested.