The 'rules' of all the secrets Santas I've been involved in, require the organiser to putall names of gift participants into a hat then the gift givers secretly draw one name out, and purchase a gift to the agreed limit for the named participant, wrap it and then put it anonymously, with a gift label with the recipient's name on it, in a sack or box for distribution at the agreed time. A variation on this theme where some participants don't have a spare £10. is to do Poundland Santa, where all gifts are purchased from a pound shop.
Static caravan purchase is it worth buying