Given:
Sales price = 319.95
sales tax = 7%
factory rebate = $30
There are two things to consider in paying for the sales tax.
1) Who gave the rebate
2) Basis of the sales tax will depend on who gave the rebates.
If the factory or manufacturer gave the rebate, the sales tax will still apply to the Store price.
If the store gave the rebate or discount, the sales tax will apply on the discounted price.
In this instance, the rebate is given by the factory. So, sales tax will be based on the store price.
319.95 * 7% = 22.40 Sales tax