I have 4 different bank notes, these being of the following amount: one 50.000, 100.000, a 500.000 note and one made of 1 million. They are quite old but in excellent condition.
For “old” you really want to go for 1950 & earlier, pre-hyperinflation series, like this P-265b 10 Pesos (& the higher the denomination, the pricier). Not worth a lot but they get tougher the farther you go back & the higher the grade: