It amazes me how much motor-driven stuff is out there either being thrown away, or available cheap at yard and garage sales. Granted - I know a lot more about small engines than the average person - but a lot of the time perfectly good machinery is for sale cheap or being tossed because of small parts missing, or gunk in a gas tank, because it's rusty and nasty looking, or a control cable broke that the owner had no idea where to get a replacement for.
I HAVEN'T PAID CASH FOR A PUSHMOWER (3.5 to 6 HP) FOR TEN YEARS...
When I see one out next to someones trash, I ask first if it is being chucked, and then take it home. I know I can either fix it or use it for parts. I also have the option of selling or trading any spare ones I have around.
Right now I have three lawn tractors, one of which is a John Deere that is only two years old. The JD cost me $100.oo for parts to fix it (Broken Rod - the owner just gave it to me).
My project mower cost me $50.oo, and has more HP than either of the others.
I have a Craftsman that only cost me $150.oo, but I've put a lot of cash into it customising it...
I have two roto-tillers.
The small one I traded an old bicycle for.
The five horse one I traded a wrecked 175cc dirt bike for.
It pays to learn as much as you can about outdoor power equipment, because often it only needs a little to gain a solid working piece that will last for years. If all it takes is a paint job, well shucks!
And as far as free lawnmowers go - it doesn't matter what happens to them if they were FREE, now does it?
There are a number of really good small engine self-help places scattered around the web too, not to mention tractor forums. Keep an eye peeled! You never know what you might luck into