In the automotive section at Walmart they carry heavy weight fiberglass. It looks just like the stuff we use to make/repair cowls. It is a pretty good size pack for around $3.00. It is alongside the bondo, glazing putty etc.
In the crafts section they carry basswood blocks, dowel rods, hardwood rails. Another interesting find is the foam rubber used for chair cushions. It comes in packs of 4 (16"x16"x1"thick) for just a few bucks.
Thought I'd pass this along.

WCB

if i buy epoxy now a days i get it from walmart. they carry 2 minute 5 minute and 30 minute.

I've been using their (@Walmart's) heavy glass cloth for many years....and yes, it is a lot cheaper than at the hobby store!

The foam rubber used in chairs can be several types. Some of the most comfortable is actually not very shock absorbing. Look closely at how the rubber "works" before you buy it. The rubbery stuff sold in LHS really is that way on purpose.

It works pretty good. I've used it in a bunch of planes and no problem so far.