The first thing you should know is that it's cheap. For just $10 a month, you get five samples. This month I received a face peel, tinted eye cream, perfume, lipstick, and a hair mask, plus the box included a code that would save me $10 on my next $50 purchase (which together is easily worth $10).
Birchbox always includes a card that lists out all the samples and the prices, which is super helpful for me to note things like, holy shit this perfume costs $90. Note to self... do not fall in love with this perfume.
Truth be told, I've been subscribing to Birchbox for three years now and I've only purchased a full-size product one time because this fancy stuff is expensive and I'm thrifty. But I do have a drawer full of the samples that I used and loved and I'm saving them in case a big stack of cash comes my way (I'm looking at you Kiehl's Midnight Recovery Concentrate).
Another thing I love is that it's always a surprise when Birchbox shows up the mail so it's like getting gift you're not expecting. I hate getting the mail because it's always bills or coupons except for that one day a month that's Birchbox day and I get to unwrap an adorable package filled with presents.