As I have mentioned before, I collect vintage unused lockable five-year diaries. I find them on Etsy and eBay for about £1 to £5. Sometimes I get the diary free but just have to pay shipping. These little diaries were extremely popular from the turn of the 19th/20th century to about the 1970s but many of them popping up in junk shops and estate sales are unused and in perfect condition.
This one is from eBay