Trying makeup at a lower price before you buy

Someone please tell me if this is weird but before spending upwards of $70 on a hyped makeup product, sometimes I’ll find an unopened-unexpired one on Poshmark or eBay and get it for less than half the price. I just did this for the Chanel water tint- it came packaged and unopened for $40. Linked a seller I’ve ordered from before!