When a countermark cannot be identified precisely, its value is usually small. I would not expect this one to sell above €5─10 unless there is some way to determine who or what "M P" was.
It looks like the two sides were stamped with the same set of punches and, therefore, are related to each other. I'll say it for the record, though it is probably not very meaningful, that "M P 28" was punched before "100". I tried to find other such tokens, but nothing turned up in Google Images.
What could it be? Perhaps a check of 100 of some produce identified as MP 28. You pay, you go at the delivery counter, and get your 100 of ____ upon presentation of the token. This is obviously only a hypothesis.
Labour was payed in 'tokens' in that era, so they could not spend there income for alcohol or liquors
It is indeed very difficult to find the origin of such a countermarked coin
Non est totum quod splendet ut aurum
Rijkdom bestaat niet uit het hebben van veel bezittingen, maar in het hebben van weinig behoeften
If that's what it is, such a piece would be called "work tally", "labout ticket", or "labour check". I was just reading about an 1893 Canadian large cent countermarked "LORDS COVE 80 12 8" on the obverse, and "FISH MONEY" on the reverse, all letters punched carefully one by one (Canadian Numismatic Journal Jan/Feb 2009). Lords Cove seems to be the location of that name in New Brunswick rather than Newfoundland.
