You get the drachma for the wind bag by cleaning the three grafftii signs off the Temple of hades. See the worker there and clean them carefully to earn your one drachma.
You use it to buy a wind bag at the very end of the game/island on your way to defeat Zeus.
You use the drachama for a bag of wind.
On Mount Olympus on Mythology Island, you can buy a bag of wind from Aeolus at his wind wagon stand. You need one drachma. The place to get it is at the Temple of Hades, where the worker is wiping away graffiti. If you talk to him, he will pay you to help him with the three vandal signs.
Near the final battle, you go inside the gates of Olympus, and there is a wind bag stand run by Aeolus. Use your drachma to buy a wind bag that will help you climb up. (If you miss the ledge, refills are free.)
In the final part of Mythology Island, you will climb Mount Olympus to battle Zeus. The only way up is to use a "wind bag" sold by Aeolus at his Wind Wagon. To buy one, you need the one drachma you earn by cleaning Hades' temple.
There is no way to climb to the top of Mount Olympus. You will need the wind bag to reach the upper ledges. Clean the temple of Hades of graffiti and the worker will give you a drachma. With this, you can buy a wind bag from Aeolus.
The one drachma you can earn is from cleaning graffiti from the outside walls of the Temple of Hades. The worker there will pay you when all three signs are totally erased.
Late in the game, on Mount Olympus, the one drachma will buy a wind bag from Aeolus, to help you climb the mountain.
If you clean the graffiti from the outside of the Hades temple, the worker will give you a one drachma coin. When you reach Mount Olympus, the coin will buy a wind bag from Aeolus at his Wind Wagon. It is the only way up the mountain.
It will not buy anything in the Town. Near the quest's end, you use it on the climb to Mount Olympus. It buys a "wind bag" from the stand run by Aeolus.
All you have to do is go to the Temple of Hades and wash the three graffiti signs off the building. (Click on the graffiti and wave your mouse over it.) When you are done, the worker will pay you one drachma.
If you clean the graffiti from the outside of the Hades temple, the worker will give you a one drachma coin. When you reach Mount Olympus, the coin will buy a wind bag from Aeolus at his Wind Wagon. It is the only way up the mountain.