This is something that you cannot find in an ebook. Firstly, you cannot get a ebook for next to nothing second hand. And if you do find a second hand book, this kind of stuff happens all the time.
Last night as I was tearing through my current read (The Enemy by Lee Child), I discovered this $4 receipt for parking that somebody paid for decades ago.
It just dropped out onto my chest, 18 years after it was paid for in Toronto in 2007. Conceivably, it could mean that nobody else has read this book since (the book in my hands here is itself a 2007 edition…), or maybe every other owner of this book had just simply decided to keep this receipt inside after passing page 280.
I like stuff like that.