[codefox1]

If you mainly aim at tuning old AM radios, a heathkit or Eico can usually be had for very little fro whaterver local ham festival or even EvilBay. Of course you have to treat it as an old radio and recap, check resistors, etc... The other accessory is a frequency counter, and a modern digital one can be had cheaply (less than $30) from same source or wherever.
Many were built from kits, so quality varies. If it is an old one you will have to be patient.

Between the two, and leave #1 on an hour or so, you can get very accurate, or good enough standards to align radios. Note bene all these signal generators will put out significant harmonics (actually that's how they work!) so you can be led down the garden path if a golden screwdriver has been in your set before.

You can get a good enough frequency counter surplus or new digital meter with frequency determination or whatever for less than $35 if you scrounge around. It's not a heartbreak if you bust one of these out, just a mild kick in the you know where.

I recently found a radio that was tuned to 1/2 IF, and still worked a little, but once I got it back to where it should be, it's a champ. Not many of newer ones would tune as low.

Anyway there are a number of ways of doing away with signal generator by using a not screwed up radio next to your set, well covered here and on net.