Look around on garbage days, there is always lots of stuff out there. While not exactly ideal welding practice material, these are examples of what is out there.
There are always BBQ's (Stands), hockey nets, exercise equipment, gazebos, patio furniture, office dividers (square tubing).......the list goes on and on.
Bed rails can be used, but I find some weld "funny" so they may not be ideal to learn on. Right now, I have some "T" posts (snow fence) that seem impossible to weld. They appear to have a coating (Cad. or galvanized) and after being ground clean they will not weld. So be aware......
If you can find a friendly scrap yard, get some mild steel barstock to practice on.
This is some of the junk I threw out last summer...I needed the space in my shed to store other stuff. Some of those pieces would have been useful to you.
EDIT:
Check out these guys...they are close by and probably have a junk box to look through. (saw them on KIJIJI)
http://www.bossteel.com/