This one:
Mac 610 Timberbear, vintage 1977. Selling price back then: $170.
I still have it and it runs today. My Stihl MS361 replaced it as my "go to" saw, so now the Mac rests in piece. However, it's fun to run the old beast, heavy as it may be. Think of it this way. I could replace the 361 with a 362 for $770--a mere $600 more. I wonder how long it will take before I ever do that?