Carbon Fiber is pretty inexpensive here:
http://graphiteelegance.com/catalog/index.php?cPath=1
I would buy it there if I ever needed it.
Go here:
http://www.industrialmetalsales.com/Aluminum_Plate.html
And send these guys an inquiry asking how much the aluminum would cost. They carry 6061 and 7075. I just sent an inquiry to them earlier today asking about the cost for a sheet 1/8" x 12" x 24" in 6061, and I am waiting to see what their price is.
Normally, I would buy from Speedy Metals on Ebay for 6061-T6 aluminum. It is very cheap there, but they don't seem to have any single 1/8" x 12" x 24" sheets. Look here:
http://stores.ebay.com/SPEEDY-METALS...QQftidZ2QQtZkm
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz