I'd say more like $225-$250. But it depends on the hardware, condition, and setup. I paid $600 for My SD3 with a pair of CMB 45 CAM motors and pipe. I'm reworking the radio box and tank setup, and will run one of my MAC 45's in it. Hope to run it this fall.
I have a lightning fast Viper 45 with all Speedmaster hardware FS, that hasn't gotten much interest at $225. Had some lowball nibbles, but I'm not willing to just give it away. Maybe I'll just use the hardware somewhere else.
I also gave about $250 for a rigged 67/80 CF SD3. Just dropped in my MAC84, and away I went. I'm redoing hte fuel tank setup on that one right now. I'd rather use a metal integral sump tank sized for hte actual fuel burned. I'll put a separate 10~12 oz plastic tank in front of the metal one for water ballast. Just my personal preference.