I am not a financial advisor, seek a professional.

My opinion: if you're young, invest...now....and change nothing else about your life due to that money. Keep reinvesting the return. At some point, you'll see you have over a million dollars and you'll keep the snowball going -- and you'll find you can retire 10-20 years earlier than everyone else. If you're older, still invest, but you may want to see what the best options will be for yielding good returns toward retirement.