I *finally* went by ProtoFab at lunch today. $100 bought me 6 2"x1/8"x6' flat bar, 6 1"x1"x1/8"x6' angle iron, and 4 1/2"x1/2"x.065x4' square tube. That's about 10 times cheaper than Home Depot.

Now I've got enough stock to build those seat rails and a welder cart.
Looks like I'm welding this weekend!