Remembering from about 2 years ago:

$10 for Marushi
$130 for rear wheel/rim tape/cog/lockring/tire/tube (ordered from LBS and they tensioned and installed everything for free)
$20 for discount bin seat

$160 total. That got me a decently working fixed gear. Over the next year or so, I switched some things out and spent a little more money, but for the purposes of the OP, I didn't include them.