There are flyable planes for less than that. Not as good mind you, but there are cheaper options if the goal is to simply get in the air.

Here's a page that has some decent ones. The Bixler is an old standby for the "cheap and simple" crowd, which I don't mean in any way as a negative.

https://hobbyking.com/en_us/hobby-pl...r-trainer.html

Now, all that said, there is one thing the planes don't come with- flying skills. This hobby is a skills based activity. You wouldn't buy your child a 900 horsepower race car and turn him loose in it because you understand he doesn't know how to drive it. You wouldn't put him on a set of skis or give him a rifle to go and shoot without proper instruction either. This is no different. Many people get into this hobby because they are looking for a toy, thinking all there is to flying is deciding that you want the plane to stay in the air and follow your commands. The technology is there now to make them do that, but it'll cost you. What's a lot cheaper and far more satisfying in the long run is to get with an experienced pilot and get some instruction. I don't know what your budget or level of commitment is for this, but joining a club is a great way to learn. If that isn't an option for you, then the AMA's website has a park pilot connection that could possibly get you in touch with someone who will teach your son to fly.