Do Oxfam sell new products? -

Yes == as you would discover if you visited any Oxfam shop :-)

What do you have to learn to learn how to do sales tax? -

you need to be able to multiply and add..

Depends on your state (and city, if there s a local option tax.), but generally speaking:Apply to the state for a sales tax number.Collect the tax.Return it on a monthly basis (usually, sometimes quarterly) with a form.Same goes for your city if they also collect a sales tax.

Where the % button is on the calculator

Why will people pay to get something fixed but wont pay to figure out what needs fixed? -

they want the problem to be solved, not to be told that there is a problem