Yeah it's a Cali and Ma thing, working in the industry, if I place an order here in Illinois but its shipping or the clients account is based in California they pay tax on the non subsidized equipment cost.
Don't buy phones from any carrier at a discount. #1. You will have to pay sales tax on the entire cost of the phone. #2. By buying discounted phones your resigning a new contract and service plan for 2-3 years with your carrier and your making inflated payments to cover the cost of the phone that the carrier has prepaid for you. In Europe and about everywhere except the U.S. most people buy phones outright and aren't locked into a service plan for 2-3 years. Take notice that all the carriers in the US are now offering prepaid services at 1/2 the cost of their contract service plans. When you buy a phone outright depending on the network type CDMA or GSM you can switch carriers anytime and still pay 50% less than being locked into a contract.