This hobby seems to be growing more and more all the time. For something that you would acquire for free at an event or off the counter of a store makes it worth while collecting. However, if your purchasing anything vintage you could shell out a few bucks. Most of mine come from a collection in which i purchased for $180 for over 400 vintage hockey pocket schedules.
Some pics below of some of my older stuff
1974 Canada -Russia Series
This one is my favourite. I've had it since the series took place.