I second the craigs list option, but be sure to test drive anything you're considering buying. Run it at all speeds and listen for scary noises and watch for high vibration. You don't want a saw that uses pinned blades, they won't fit through small holes if you are doing any inside cuts.
If you see a saw that is interesting try and get a model number, then do a reviews search to see if it gets good reports. Or run it by the crew here for their opinions and experiences.
Old saws may be hard to find parts or even a manual for.
My brother lucked into a DeWalt at a yard sale for $75 in near new condition. Kucky dog!
Just shows you never know where you will find a bargain.
Don't get in a hurry and buy the first thing you see.
Gabby