Sales taxes are considered to be regressive tax; that is, ground-level income people tend to spend a greater percentage of their income in taxable sales (using Use Tax a cross section time-frame) than below income people. However, this calculation is derived when the tax paid is divided not by the fine base (the amount spent) but by income, which is argued to devise an arbitrary relationship.

Determination of ways to legally reduce the amount of assessment due on a transaction. For instance, how a company structures its invoices can affect the taxability of the entire transaction. In copious states an item can become taxable if not separately stated on the invoice.