Earlier quoted context omitted.
No, I'm using 'n' to deal with websites that periodically require you to change password and enforce that you use a new password I suppose I could also do it as master_password + '/' + domain + str(n) or something like that.
Ahh, ok then how about using the DateTime at runtime? That would then save you from having to keep "n" stored elsewhere for future uses. Edit: nevermind, this would prevent you from retrieving the password - I had in mind a password generator, sorry.
For consumer use cases, you should use sources of noise for this, such as microphone noise, mouse movements, fluctuating voltages, etc. If you wanted to be super-secure you would use a quantum random number generator, which is truly random, but unnecessary for the threat models of most consumer uses. Just use anything but date/time. The random number generators of most modern languages and operating systems already have such measures in place.