RE: :Tip for Rx. padding
I have to agree with using foam for padding. If you need a cheap (a.k.a. free) source for foam, go to you neighborhood computer shop. I own a computer shop and I have supplied all of my flying buddies with enough foam to last them for a couple of lifetimes. Most of the equipment we order comes packed in high quaility foam, or "egg crate" foam. Most shops throw it away. Take them a garbage bag and explain what you want it for, and I'm pretty sure they'll save it up for you. Depending on how busy the shop is, you should have enough foam to last you forever in no time at all.
P.S. IT departments at larger companies usually have plenty of foam too.
Hope this helps out.