I've wanted to try a subscription box for a while but I can never find one that has value for me. If you shop sale items on a regular basis, the sub boxes end up looking expensive. I'm also not sure I buy enough of one specific thing to want more every month or every season.
I am very careful about my subscriptions because of this. So, when it comes to the cost issue, I look for subscriptions that put together items that would be difficult for me to get myself. For the Japanese snacks, for example, bokksu ships directly from Japan and I know that these are not things that can be purchased here. I usually go to Japan once a year, but I would not buy this kind of variety because it would be expensive to get an entire package/box of each kind of snack.
The way I look at it, I am paying for them to curate the box and ship it to me, rather than the price of the individual parts. I don't subscribe to things that I could easily find in a shop myself or just order through amazon.