Walmart offers a free seasonal Beauty (or baby) Sample Box Subscription for those who want to try and review new products. You’re only ever billed for the shipping, which is a reasonable $5.
As a Walmart Beauty Box subscriber, you will receive a custom box each season filled with brand name product samples, all available at Walmart for purchase. Each Walmart Beauty Box is a limited edition and may sell out at any time.
They also have periodic contests for those who post reviews on Instagram. The current prize is a $50 e-gift card.