re: Advice you'd give your son

First make sure you have an emergency fund that covers 6-12 months of expenses. You can put it in a money market or short term treasuries. After that, max out any 403b, IRA etc you have access to. If you earn a high income you may want to go pre-tax, otherwise you might be better in a Roth. Regardless, with such a low 401k, you need to invest almost entirely in equities to make up the shortfall. Pick a low fee index fund from Fidelity or Vanguard.