All kinds of things out there, but at age 10 lots like the pictures. Just get some of the used magazines hanging around dingy Helicopter offices......Heli-Ops has the best, others follow . If he is a reader then he will pick up the articles from the related pictures.. After a while if he enjoys those, then maybe something technical.
Its a bit cheaper and you can tell if hes serious..
I also saw a game where the Helicopter was operated on a battery and went in small circles. It sat on a smalltable. One could hover etc and pick up a load with the thing. It was cheap, just cant remember the brand.
It always made me look bad.
Good Luck.