I've recently discovered that there are a lot of coins and medals included in first day of issue stamp envelopes from around the world and some are not to badly priced does anyone collect these? If you do are there any that would be more collectable than others? I've got some distributed by Mercury they seem to be quite common and I have seen some distributed by Benson. Most have an issue number on the envelope I know that will be for the number of envelopes issued and not the coins does anyone know what he maximum issue figures are for these envelopes. My main coin/medal collecting theme is the Royal Family.
Hope this is not to vague thanks for any information.