From the title of your post, I was certain that this was spam! Anyway, here's how it's done:
The wad of notes is in the dessert parlor.
After taking the wad of notes:
say "You grab a fistful of dollars, and shove them hastily into your wallet.";
remove the wad of notes from play;
if the money is off-stage, now the money is carried by the player;
now the price of the wad of notes is $25.00;
increase the price of the money by the price of the wad of notes.
The extension itself points the solution when it says you can decrease things by the price of other things. This implies that you can increase things by the price of things.