Totally depends on which cessna, how much, and what kind of shape it's in. As garcfield said, giant scale planes usually don't run on .40 engines. I'm guessing the kid at school has never seen anything bigger than the 12 inch static models at the toy store, so anything over 24 inches is "giant scale". I was the same way before visiting a hobby shop for the first time. Also keep in mind that while many people learn to fly on full scale cessnas, they're not all trainers or even good 2nd planes. Cessna has made a lot of different planes over the years and some could probably be a handful. So it does make a big difference which model it is. Make sure you check it out before offering to buy it. All that being said, buying planes used from other people in the hobby can often lead to some great deals on nice planes. Good luck!