Personally, I buy 99% of my makeup online, unless it’s foundation or sale items from Sephora. But before I buy anything, I research to see why something is cheap, or if it’s repackaged, etc. Because buying fake makeup is dangerous, (more on that here) and buying repackaged mica is just a rip off. After all, why would you buy an eyeshadow from an indie brand if it’s just factory mica that you can get from a wholesaler, cheaper, and with more product?? So if you’re buying online, I BEG you to do a google search on the store you buy from beforehand. It will save you money and might actually keep you healthy. Fake makeup is unregulated and you dunno what could be in it.
So, if you want to buy MAC makeup online, PLEASE be wary of buying it on ebay or some website advertised next to a youtube video (99% of the time they’re advertising FAKE MAC brushes, pigments, etc.). Here are some reputable websites you can buy MAC or other high end makeup without worrying about them being fake: