Check with a tax adviser for your particular situation, but it could possibly be deductible on your federal income tax return, if you itemize, and have enough medical expenses to get over the hurdle.
Not all of the spa's costs may be deductible, so check with a pro on that.
Same may apply to your state income taxes.
Some states waive sales tax on medical purchases.
Not sure that you'd get a discount on the purchase price from the dealer.
