I get steel from a large steel supply place, Triple-S in Knoxville, everything from rebar to I-beams to sheet steel, hot rolled or cold. I get offcuts for cheap at a fabrication shop - I dig through their bins and make a pile of what I want and the guy looks at it and says "OK, $5" or whatever. Another place is a local metals recycling yard where you don't know what you'll find that day but whatever it is it will be at scrap prices. (We once found 1/2" titanium tubing for a couple of dollars per 10' length, new stuff. Looked it up and they cost about $200 each.)
The best place for me is in my shed! I bought 8000 lbs of surplus steel at 10 cents a lb and have been using it around the farm for years. The last time I made a tool rest I dug through it and found a long piece of 1". Too bad you don't live down the road.
But one of the handiest places IS down the road from you - the internet road. Online Metals has almost any metal you can imagine (and plastics) in lengths short enough to ship inexpensively. I've bought steel, brass, aluminum, and plastic stock from them just to have on hand to use with the mill and metal lathe. I've had good service from them.
Here is cold rolled mild steel round rod, perfect for tool rest posts: https://www.onlinemetals.com/merchan...=2&top_cat=197
JKJ
Ron,
See if there's a Fastenal store near you. They have 1" bar.