You laugh.

I just got a rebuilt 727 ($1,200), with a Mancini Racing valve body ($389) and shift kit ($200), and a new 2,500 converter ($349), for $500 (plus $60 or so in gas to drive and get it). That's about $2,138 worth of hardware for $500.
And yes, I have seen a833s, rebuilt, listing for that amount. I'm guessing they're actually selling for less. My son's boss just bought one for $600 that was for a failed Charger project. Rebuilt, came with new clutch gear, bell housing, and the levers to connect to a pistol grip shifter.