i got my hard form padding from the army surplus shop, you can get it either from beach road or anywhere else.
I bought a $12 foam mat, which is around 1.5 metres. it was previously used for exercise and picnic, but i converted it into extra padding for my bag. Do check the quality, as there are a few types of foam. Buy the one that is springy in texture, thick and make sure you get compressed foam!
Got my velcro from spotlight at $4/metre. (iron on my velcro to make little foam compartments)
waterproof cloth (plastic coated) to iron on my camera bag. around $9/metre
for cheaper version, and those who are good at sewing, you can get the non iron on stuff which is 50% less