@Ren Tanner How fortunate to have had the opportunity to live in NZ! One of the possible choices I had made years ago, as I prepared to leave Crook County, Illinois!
I really try to buy only brands and sizes I know will fit when shopping online. As mentioned above, sizes and cuts can vary greatly from one manufacturer to another. Sometimes it helps to look at the country where it's made, if you're familiar with their sizing. I have trouble with shoes even in person, so I've finally learned not to buy them online. I buy two kinds of face cream online and am happy with them because I know what I'm getting. I agree, colors can be difficult to gauge, especially with makeup, but I've also been surprised when some clothing I've purchased online has arrive and is markedly different than that shown in the pictures.
There are actually some stores out there that will accept returned used beauty products. CVS is one of these stores.
Walgreens does also, meaning you tried it at home and didn't like it....not used half of it and returned it, don't think they'd go for that....but who knows, they have to throw it out I would think.