Hacksaw and a good set of files will cost less than $100. You should get a good hacksaw, and good blades. Lennox makes good ones. I think we just talked about files recently. You want a half round bastard cut file that matches each tubing diameter.
If you go with a tubing notcher, get fine tooth hole saws.
These for example Get mandrels from Strawberry or Paragon (UBI sells Paragon or order direct) There are two sizes of mandrels depending on the size of the hole saw, get one for each hole saw. I'm setting up my lathe to cut miters, but that's a bit of an investment.