You should be able to pick up an OEM Rega RB-250 or RB-300 for under $400. They are very nice simple tonearms and are fun to tweak. You seem to be into the DIY so you could buy a RB-250 and then do a rewire and get an upgraded endstub and counter weight as the urge hits you. There is a very interesting thread that was going around some time ago about the strange tonearm tweak for Rega arms that looked really cool.
An used Audioquest PT-6 or Sumiko should fit your budget too.
Cheers,
Jim
An used Audioquest PT-6 or Sumiko should fit your budget too.
Cheers,
Jim