Another way is to get a Santa Hat for like 300k and go to world 1 and sell them for over 1 mill each. (I never did this and I wont because I would never spend 300k on a hat.) :P
P.S.
This is stupid, dont waste your money on this or your time.
Why am I posting this hint?
Peter (when he's hungover): This sucks worse than that time I went to that museum. (Flashback to childhood, standing in front of dinosaur skeletons.)
Peter (as a child): Why did all the dinosaurs die?
Man at Museum: Because you touch yourself at night.