Well here is my not so fancy but cheap version. I went to Chase Pitkin (local box store like Lowes, Home Depot) and bought 4 swivel casters rated 90 lbs each @ $1.99 ea.
I had also went to TSC and Lowes, but their prices were higher and the only one that the ones like Dennis showed with the threaded rod was TSC @5.99 ea.
I decided since I had no metal and no real way to easily work with it anyhow I would use wood.
I cut some wood pieces 8" long by 2" wide for mounting the casters. Then trimmed the balance of 6" to just under 1 3/4" to fit into the stand ends.
I also had to shave the thickness as they were too tight to easily go in and out.
Here are the pictures of my setup.
I will probably end up re-making the wood pieces and increasing the size where the casters go as I did crack a couple when putting the screws in, but I'll see how long it hold up. I will probably go to hard wood for them as well.
Worked great getting the bagger off and moving around the garage, but was too late to mess around with re-installing it so haven't tried that yet.
First pic is off the wood cutout and marked for the casters.