If you are buying something with a core charge on it from a parts store, buy it online. When you buy it online there is a loophole and you will get your tax money back from them. if you buy something in store with a core charge of $100 you pay $107 after taxes for that core, then you return it, and you only get $100 back due to state of Ohio laws apparently. However, if you buy online you get $107 back free and clear.
p.s. if you buy parts online at advance auto, you can almost always find a coupon for 25% off.