How much does “back to school” cost?

As I was typing up the school supply deals for this week, I started wondering: how much does it really cost to go “back to school”?

I was homeschooled and don’t think we ever bought school supplies as an “event”.  I’m sure we bought a few notebooks and pencils, but pencil boxes?  Staplers?  Post-It notes?  Sharpies?  No need for a backpack, for sure – though I do remember buying one when I attended my first courses at a community college when I was in high school!

So, I’m just curious: how much do you spend on “back to school”?  Do you buy absolutely everything on the school supply list?  Is this a time of year that you buy your kids new clothes?

What have you found to be necessary, and what can be skipped?