I believe it was a competition that raised the money. A common game back in those days, and still in some parts on Europe today, called "Nageln"
You have a tree stump, about waist high, and hammer a nail into it, just so it stands up. They you give the hammer to the person who bets he can hammer the nail completely into the stump, in three goes.
So it would be like at a fun fair. Thats the kind of game it is, we still have it over here, but in Pubs and Winterskihütten, great for drunk people who believe they can do it. And so each person that tries, pays a certain amount to "try". Of course it is much more difficult than it sounds, so almsot nobody actually wins.
This is more than likely what this was, a game of Nageln, organized by a certain group of HJ, to collect money. This letter is just the person sending the confirmation of the total collected amount by the HJ for that game.
If you win, there would have been a nominal prize, but in this case it was more about offering "something" to collect money, instead of just standing on a corner shaking a tin.
It is, also really more a game for drunken people.