I recommend looking into this site:
http://www.nihonzashi.com/
Cheap and katana do not go together.
If it's cheap it's not a katana. Real Katana cost tens of thousands of dollars. Something like a cold steel or Cheness katana style swords go for hundreds of dollars.
eBay or watch the cutlery corner on tv late nite. It's a knife show they sell tons of knives and swords most of them are in the cheaper side but they occasionally sell some decent swords that will last a while
At a martial arts supply store, where else would you get one.
title explains it, I want to get a usable katana where the blade is pretty far into the handle and i want it to be steel, not metal. I also want it to be cheap and i want it to be able to cut