Years and years back, there were these cardboard albums that you would put together a set and mail it in. The company would mail you a check for the set. Were these called Premium Boards, Premium books? I'm looking for an image of one from about the 40's. There is a guy on one of the forums that collects old stuff like this. Any idea who I'm thinking of.
David Lange is who I was thinking of. He wrote the book on the topic. Found an image of one of these boards on Ebay. Needed it for a different thread. Looks like they were called Premium Cards.
Do an ebay search for 'coin board.' There are always a few being offered. I may be misinformed but, from what I've gathered, these were manufactured by Whitman as a means for collectors to display their coins. It looks like the originals were made in the 1930's and 40's. Whitman then moved on to the coin folders we see today. Idhair is correct, David Lange has written a book on these boards. He has a website that you can take a look at. If anyone has any more info on these, please post it! Hate to start a new collection but....these intrigue me.