Apple is not compelled to pay (and collect) state sales tax if there is no company owned retail outlet or headquarters with in that state. So if Georgia has a an Apple store and you live in South Carolina and there is no Apple store in SC, then Apple is not required to pay and collect sales tax.
But- Many retailers have started collecting and paying sales tax for orders, regardless of weather they are compelled to or not. They are doing this not to make money, but rather avoid paying when/if congress mandates that sales tax be levied on all cross-state orders. It hasn't happened yet, but it a debate topic that comes to the surface every year. (If it does happen, they might try to make it retro active).
Now for Turkey. If you purchase a computer using
Turkey's Apple Store then you should be subject to what ever import taxes and local taxes they apply. (It looks as though Apple has subcontracted or is working with 3 companies to sell Apple's in Turkey)
If you purchase in New York the worst sales tax should be 8.5% (multiply by 1.085 to get the total). AppleCare is not taxed (services are not taxed) and if you get footwear in NY I don't think that your taxed. If you happen to be going to Washington State, not DC, I believe that there is 0% sales tax. I hope that this helps.
Off toppic:
toughboy One of the countries that hope to visit soon is Turkey. If you had two weeks to see Turkey, what would you suggest visiting?