Tax Exempt for Charities

[adellaguardia]

I've been looking around and not having much luck. Is there a way that customers can be tax exempt for charities or other reasons? It doesn't need to be validated against a system or anything, just a way to mark themselves tax exempt and not pay taxes on the order.
Thank you!

[aftertaf]

shopper groups and calculation rules ?

[Studio 42]

You need a shoppergroup switcher, some do this after registration in some condition, you cannot use it for anonymous user.