I live in Ohio near Indiana. Some Indiana dealers advertise “If you don’t live in Indiana, you pay no Indiana sales tax” as an inducement. So you buy the vehicle (no tax) and take delivery in Indiana; they send the paperwork to the Ohio DMV, you get your Ohio title then pay Ohio sales tax when you register it.
If you buy from CarMax, expect to pay about 25% over the NADA book value. CarMax does offer some nice services, but compare their prices for similar vehicles to any independent dealer and you’ll see what I mean. Our local CarMax has a set test drive route that one must adhere to, AFTER the sales person gets the vehicle pointed toward the street. Then the sales person goes along, regardless of the age of the prospective customer.
Remember MAX is the last name in car buying,.