Chromebook recommendation

Don't know how large of a device you'd like to get, but I recently picked up a Lenovo Duet kinda hybrid tablet/laptop and I love the thing. $300 and comes with a typecover that is solid. Runs smoothly unless you to run a ton of tabs.

Does your son's school have a recommended brand / model?

This 11" Samsung is a good low end CB - light weight, good battery life, decent speed, fairly rugged... LINK

Have 2 of the lower end Acers at home, I think less than $250. Never had problems out of either. Son used his at college and might occasionally have an issue with a certain class, but almost always had a fairly simple workaround.