if you want the money to go to the person who killed it, then the action is - add 100 gold to owner of killing unit.
I don't know about leader boards... but you could set the wood amount as the number of kills, so on the same trigger also put - add 1 wood to owner of killing unit.
The leader board on kills can be based on each player's amount of wood.
Um, you could just simply have an initialization trigger that sets the owner of the units that you want to give money to give a bounty. Then simply, (using the object editor) set the amount of gold bounty to 100.
(this deals with the leaderboard)
Set up a leaderboard, (I am assuming that the link above shows you how to make one) then make a variable to represent the number of kills for each player. Then have it update everytime a player kills a unit.