material for slide bushings

hi,

i am reading the list for a while, and would like to hear your choice:

(i am absolutely amateur in machining, education in electronics and
informatics)

i am planning to build a small mill. cannot afford too much for the
project, so commercial linear
guides are out of reach.

the question is: what would You use for the bushings on a 1/2in steel
rod/maybe aluminum.

1. UHMW-PE
2. teflon filled PA (Poliamid)
3. i was told that there is some special PA, that is filled with some
solid lubricant and/or oil, used mostly for the sleeve in sliding
bearings.

thanks for replies.

vajk