it comes with a 950 coil as standard issue and that might be on the large size for most newcomers. It would depend upon the type of detecting they are going to be doing, but since most hobbyists are coin hunters, and since some coin hunting is done in trash infested sites, a better coil size would be 8" or smaller.
The Classic 4 is essentially the former Classic II. A simple yet very efficient 2-knobed, turn-on-and-go model without any Target ID. The only differences are that the Classic II and Classic ID came with an 8" coil as standard, and the Classic II didn't have any modern accessory coils available for it.
The Classic 4 and Classic 5-ID are special made for Kellyco with a slight modification from the former Classic series so that they operate at about 8.1 kHz and therefore use the same coils as the newer Prizm series.
The Prizm II, II, and IV come with an 8" coil, and the Prizm V comes with the 950 like the Classic 4 4is equipped with. At present, there are no other coils available for these models, however I was told that White's is working to address that shortage and is trying to develop a smaller-size search coil for the Prizm series.
You might want to consider a used model for your son, or perhaps a current Prizm model if you want him to have Target ID while staying in the price range you've established.
Personally, I like the Classic series physical designs with the rear-located headphone jack and the very long battery life. If he was going to be hunting more open areas for a while, such as a beach or maybe soccer, football or other sportsfields, or the larger open areas at parks, the Classic 4 w/950 would do just fine. Then, after a smaller coil is available, you could buy that and use it when hunting in trashier playgrounds and by picnic tables, etc.
I know how well the Classic 5-ID performed, because it retained all opf the excellent Classic series characteristics, to include the quick-response AND quick-recovery. The Classic 4 is the same way and would make a very good detector.
<EM><STRONG>Monte</STRONG></EM>
