Ok sorry to but in as the new guy, but you can get good results with a weber kettle as a forge for heat treating, a set of files, and lots of patience.
My best guess since you will have most tools already (or at least it seems that way) will be
Old file (the older ones act like W1 which I assume will work well for razors) for cheap or free
New files (for working the old file) probablt $30 for two or three
Forge (a hole in the ground with a hair dryer pointed at it will do) Free
Drill Free (if you have one)
Scales It really depends
You could probably (if you are a master scrounger) make a razor for under $50.