🚀 go-pugleaf

An old Frigidaire upright freezer was left on the screen in porch of a house 
we are buying.

The freezer clearly works (lots of built up ice/frost inside) but has some 
real problems.  The door seal needs to be replaced but more seriously, the 
bottom of the front door has some serious rust, so much that I can push in the 
metal and feel the inner insulation.

Not sure if the thing leaks air badly; there was some water beneath it, but 
this may be due to the bad door seal.

Questions:
1) I was thinking of sanding off some fo the rust and painting the thing w/ 
rustoleum.  Reasonable?  Can I just ignore the corroded metal, fill it in, 
etc, and have a working freezer?  (A freezer isn't critical, but we need to 
economize so it could be helpful)

2) How uneconomical is this thing likely to be?  I've seen chest freezers 
posted on tri.forsale for as little as $75.  Is this upright so old that it's 
likely to be very expensive to run?  

3) If I wanted to get an answer to 2), what do I need to know?  The wattage of 
this thing?  Is there some device I can plug in between the outlet and the 
freezer to measure its power draw?

Thanks for any help.