[DonRotolo]

Many plastics make good bushings if not compressively loaded much. Sintered bronze is the classic material, plain bronze and brass are OK. Aluminum is not that good as it tends to gall under load. Steel isn't as bad as you might think, but must have lubrication.

For the 3" range ball bearings are not a bad choice (and not as expensive as you think), and if there are axial loads a tapered roller bearing would be good. Just look for low-speed versions if price is an issue.

You could cast some Babbitt, but that's way old school.