Is all state sales tax a federal deduction?

In theory yes, in practice, no.

Only when you can qualify to use the schedule A itemized deduction of your 1040 FIT tax return during the 2014 tax filing season and that total amount from the schedule A would have to be MORE than you EARNED INCOME standard deduction amount of 6100 that would be free of the FIT amount during the 2014 tax filing season on your 2013 FIT return.

Hope that you find the above enclosed information useful. 10/22/2013

You may deduct either state and local income taxes or state and local sales taxes, whichever works out best for you. If you choose to deduct the sales taxes, you may either use the income based safe harbor amounts in the Schedule A instructions or the amount that you can prove with receipts. If you choose the safe harbor amounts, you may add the sales tax paid on big-ticket items like motor vehicles, RVs, boats, aircraft, etc. that you can prove with receipts.

Technically, yes.

However, you can deduct only state sales tax or state income tax, not both. Deducting state income tax is usually a better deal, so most taxpayers don't deduct state sales tax.

If you itemize and if you have a large purchase, then maybe. For most people, the state and local income tax deduction is better to use.

sales tax is only applicable on sch A and that allowance includes all states

in your friend's case if he has receipts that exceed the standard that is allowed on sch A(pertaining to income, household income and number of days in the state) he can claim what he has totalled in those receipts

You can keep track of every penny or take the default amount (plus major purchases). It's a choice.