Reality Askew

I watched the Space X explosion today and was sad that so much money, time and effort had been put into the launch only to have it end in a giant fireball.  It got me to thinking, why is it so expensive to launch a rocket into space?  I’ve hypothesized in the past about the possibility of using a magnetic rail (love magnets and lasers :)) to help accelerate a ship into orbit, but my idea this time is on the actual ship construction itself.  Why does it have to be so expensive if it’s just send supplies and why the torture of creating a reusable rocket that so far has yet to land where it’s supposed to?

My idea is simple, however it’s not new.  Why not make something like the model rockets I used to play around with in grade school?  Okay stop laughing and consider it for a second.  Why couldn’t you build the main rocket structure from some super condensed cardboard (paper) type material.  I would imagine layers of paper wrapped thousands of times to create a very solid structure.  As for the rockets, why not make giant solid fuel rockets, again like the ones model rockets use?  Combine these two and you could build a simple, cheap, disposable supply rocket.  As a note, it would be very disposable because it would simply burn up on reentry.