There's two things I can never leave the house without. I'm in love with bronzer. It's nothing like the glow it gives you. I never leave the house without my Nars bronzer. I use the Casino shade, which is basically a brown with a little shimmer. It's about $30, but it's definitely a great investment. You can find it on Nars.com or Sephora.
Then there's my new favorite mascara as of 2009. Covergirl Lashblast is a great steal and it is way cheaper than Mac. It does a better job than Mac if you ask me. It's on average about $7.00.