Matterbox is a Royal Mail service.
Every so often they send out a box full of interesting stuff and freebies. The next box will be sent on Saturday Nov 29th.
This post is to let you know that new registrations are being accepted again. Those new subscribers will get the box being sent in the New Year.
Registrations close after a while so I would recommend that you sign up whilst they still have spaces left.
Links to old posts in first reply.