For infinite money, go to the Seize Us Palace (the last stage). When Asterix rides the cable car (where Obelix complains about how he never goes into the car and says "it's not fair"), you will have to cross a couple pillars to continue. On the first one, you will see a slot machine in the upper side. Loop and get Asterix to the machine. Once there, bet 999 helmets several times. You will never lose since it is an always-win slot machine.