Here are some things to consider:
Tenga Flipholes & Fleshlights
These are good in terms of buying a sleeve. Most would consider these 2 as the top of the Masturbator Game.
This is probably the only penile vibrator on the market. Totally different sensation since men aren't used to using vibrators.
With this you can buy a few, without spending a lot, and he will have a lot of variety in texture.
Another thing to consider is what he wants from a masturbator. Is he looking for something simple that feels REAL? Or perhaps something that is crazy, and is PURE pleasure? This will help you a lot in picking one out.