In theory you could, but why? Spend the $100 more, you'll get at least 2/3 of it back in resale.
I don't have a problem with a 16 gb phone. After deleting all of the apps today that I never used on my phone, I have 6 gb of space left. I stream my music, and I don't watch videos on my phone. I have a few short video clips and a lot of pictures.