unix on the ibm pc?

[MLWLG at CUNYVM.CUNY.EDU]

I have asked been asking around if anybody knows of a unix system for
for the ibm pc (compatibles...), but the answers were no.

Information about unix and the ibm pc would be appreciated. In
particular;

 1 Does such a system exist?

 2 Is there a public domain version?

 3 Who are the software vendors?

 4 What are the price ranges?

 5 Et cetera.

 Thank You.....