I have a #4, which is a shade over 60 years old. Works like a charm. The burrs are made from tool grade german steel. Don't buy any 'made in China' ones, the ones with components made in Japan are excellent (though hard to find) as well.
I got it for $38 from an Ebayer in Germany. If you are patient and keep your eye open, you can find some phenomenal grinders for under $100.