Oops, not my thorough self when I posted that. So here we go:
Originally Posted by BrianShaw
100 and 250 Automatic use #531, which is a 4.5 volt battery.
350, 360, and 450 Automatic use #532, which is a 3 volt battery.
Both types are hard to find, though sometimes an electronic supply place will have them. Apparently some computers and other electronic gear used these batteries, though little else did. The earlier suggestion of converting to AA or AAA batteries might be an idea, though if you are not technically inclined, or have never done soldering of connections, it might be better to avoid converting. You can sometimes find Polaroid batteries on EBAY for any of these cameras. If you get the old style battery, it will probably last a few years.
I did a conversion to a CR123A, which is actually a 3 volt Lithium battery. It works fine in the 250 Automatic, though when I use 100 ISO film (669 or 690) I set the camera to 75 ISO. The 250 Automatic has 75, 150, 300 and 3000 ISO settings, and has a form of exposure compensation on the front of the lens. When you first get the camera, you will shoot a few test images to figure out where to set the exposure compensation, since most of the newer pack films you would want to use for transfers are ISO 100.
The issue of the original batteries lasting so many years is usually why these cameras have corrosion in the battery compartment. Most of the time you can scrape them clean and put a new battery in it. On really bad corrosion cameras, the terminal connector wire might be broken, which means soldering a new wire into it. Mine had broken and corroded wires, which is the main reason I did a battery conversion.
A G Studio