Third level is where monsters that can only be hit by magical/silvered weapons come in.  Wights, wererats, and the like.  So, you should have a couple +1 weapons sprinkled amongst the warrior-types.  A low-powered wand of some sort (trap/magic detection, perhaps) with about a dozen charges might be nice for magic-users.  A couple single-use potions or protection scrolls would also do some good.
As for money, in a one-off, you should just let them have whatever standard equipment they want off the PHB list.