Purchase of a new or used one is a part of the whole deal. You will need service from qualified mechanic, inspection for airworthiness, parking or hanger space, takeoff and landing fees at most airports, a pilot if you are not qualified, and fuel. Oh, yeah, washing and waxing, maybe paint, maybe updated instruments and radios, navigation equipment.
Saw on Internet a beautiful 1970s Lockheed Jetstar (the Goldfinger type) for sale for $950,000 only. Might take almost as much to get it into the air for a year. I got to fly Houston to Miami and back in the very same one used in the Bond movie in 1967. It was my father's company leased plane at time. Beautiful interior, wonderful condition then, and just as fast as commercial jet (520 knots cruise). Descended into Houston very steeply instead of go around, bopped down runway at high speed.