OK, a classical is an accoustic, but it has nylon strings, which are easier on the fingers, it has a wider neck so its easier to get your fingers around the fretboard, its lighter and comes in 1/2 – 3/4 and full size, and you can get a good one for around $150-$300. the other option is a steel string accoustic, these are steel strings and hurt the fingers until you develope hard skin to counter it, usualy takes about 3 weeks, the necks are slimmer and the strings closer together, and they genraly only come in the larger full size, although there are exceptions to the rule. My advice? ask your son, the important thing is that he feels comftable with it, maybe hes not bothered too much about the ‘cool factor’ and will happily play a classical style guitar. But If he doesnt like it he wont feel like playing it.
Good luck,