For anyone interested in makeup, I'd recommend Ipsy. Let me tell you the downsides first, though. The quality of the samples is inconsistent -- sometimes you get great stuff, other times it's a month of junk. Also, if you already have a huge makeup collection, you will often receive a lot of stuff that you already have (and possibles in a better quality too!) However, for $10, it's a fun treat to get a bag of little surprises.
Birchbox was more disappointing for me. Too often the sample sizes were so small (like single-use foil packets that you'd get in a magazine or the mail) that I didn't get to really try the product, and I felt ripped off for spending $10 for tiny, crappy samples. PopSugar is fun, but for $40 a month, I ended up dropping it and spending $50 to $80 every other month on some things I really wanted, as opposed to grab bag of stuff I might like but might not love. Julep wasn't great either -- for $20, I could get buy 2 get 1 opi colors at ulta.
