At the outset I had a pretty standard random collection of DIY / bike repair / basic carpentry type tools collected over the last two or three decades and a Makita LXT cordless combi drill.
The knife making method that I'm getting to grips with is stock removal (rather than forging) so, in order to get anywhere at all I needed to begin with a decent hacksaw, some files and a stack of sandpaper. I already had a few of these tools but they were not really the right size, quality or condition so I hunted down tool bargains where I could trying to stay on the right side of the fine line between price and quality.
So, at the top of the shopping list was; a 12" hacksaw; a 12" flat bastard file; a 12" flat second cut file; a 12" flat smooth file; and some new drill bits. For the saw and files I went for Bahco tools as they seemed to offer good price / quality. There are loads of other options out there but I reckon there's a strong aspect to tool buying that is just personal preference, experience and sentiment as much as anything - I've had a Bahco adjustable spanner and socket set for years and both have been faultless. I also like the colour orange!
The theory goes that you can make a knife using pretty much only the tools I've just mentioned - I believe this is true but my experience is that it is very labour intensive!