Got a MAC question

I am going to try to pick up a used MAC machine for testing here at home.

Let me know if this is a good price for a used machine?
Apple G4 Tower 400 Mhz This also has an internal SCSI Card, the ATA drive is 10 gig, and the scsi ultra wide drive is 17 gigs and 9 gigs. runs on OSX 10.1.5, runs great.

150 bucks.

Will it run the newest OS is that OS the current? It will mainly be used for testing multiple browsers (mac version) and mild browsing.