Yes...and it is high
I don’t know
There is no sales tax in the state of Oregon.
You do not have to report any income tax refund on any tax forms, it is not income.
No, Oregon is not one of the fourteen states that tax Social Security income.
If you were a resident of either state or you had income from a source in either state, then yes.
There are multiple states: Alaska, Delaware, Montana, New Hampshire, and Oregon have no sales tax, but they have income and property taxes. I do not know if there is a state that is completely tax-free.
Yes. Same-sex marriage is recognized under Oregon state law and they must file as "married" on both their state and federal income tax returns, although this can be done either jointly or separately.
Texas does not have a state income tax.
There is a state income tax in Illinois.
No, when filing for the state income taxes, you will receive your federal income tax refund as well as your state income tax refund.
State income tax payments are deductible on your federal income tax return. (You may deduct state income tax or sales tax, but not both.) Federal income tax payments are deductible on your state tax return in a tiny number of states.
Yes..only on that portion of income properly allocated or attributable to that State.
Florida does not have an individual state income tax. They do have a corporate income tax.