Craigslist or Kijiji in Canada.

There are 3 or 4 listed in my local CL right now for reasonable prices.

I did notice an ebay listing for local pickup as well, so keep searching.

I have an LE right now. I picked it up with a power head, hose, and all attachments for $25

Mine was used like a shop vac, and was pretty dirty inside.

Look or post in the Super Market link as well (top of forum)

Use searchtempest to search multiple CL listings.

You cannot go wrong with either metal or plastic, they are both great machines.

Sometime it is a personal preference.

The motors are smaller on the plastic bodied canisters, but still have great suction.

They are also lighter. The plastic has a tendency to look dingy after a while, but a little cleanup will take care of that. 

Here is my LE