Originally Posted by HillRider

You can buy brake and derailleur cables and housing at any bike shop. They aren't the same as the cables have different end fittings and typically derailleur cable is a bit thinner. Brake housing is larger in diameter and made differently (spiral wound) than derailleur housing. For both, buy lined housing and stainless steel cables. The end fittings (aka ferrules) are typically just slip on so no crimping is needed.

There are premade housing and cable kits available but they tend to be more costly than bulk housing bought by the fool and individual cables.