Is it better to use class variables or pass parameters?

[Derek Basch]

So, if I am understanding what everyone is saying here. I should do my
best to distinguish between values that are part of the "state" of an
object and values that are more disposable and can change for each
computation of a value. So if I create an instance of a "wallet" class
and the color of the wallet is "red". The "red" value would be ideal as
a class variable as it is tied to the state of that wallet instance.
However, if the wallet class contains a function to compute the tax on
a purchased item, the purchase price would be a good example of a
passed parameter value. Am I on the right track?

Thanks,
Derek Basch