Over the last week I've searched the internet for book box subscription services. Here's a list of the ones I liked.
Ship to USA & Canada only
Quarterly book box © Book Riot
You'll notice there is a distinct lack of UK-based book box providers. I'm not sure if this is because it's not yet taken off in the UK or because I didn't look hard enough. Either way, it means I won't be signing up for a book box subscription service any time soon. While the international shipping cost isn't generally too expensive, if my delivery gets picked up by customs, I'll get stung with a nasty import fine. A real shame for UK readers like myself. Still an awesome service for US-based readers, though!
If you know of any UK-based book boxes, or I've missed any US or Canada-based services, please let me know in the comments.