book design: solving a problem

I've been worrying a bit about how my book fair books will turn out because I'm so skint. Especially because I wanted to make about fifteen of them I knew it would be pricey but I calculated the cost of printed and hard binding each book (A4 square format) and IT IS EXPENSIVE. Too expensive. So, in the quest to make something cheap(er) but still lovely there were few solutions that I liked until I saw this. Who thought rubber bands could look so lovely? 

I'm definatley going to be 'binding' my books like this - I might look into buying some coloured bands to make them a bit more special, but I like how they are then just like big postcards. Good idea or not?