Tough question, although I think TOK is in the ballpark.
I thought I had an old Atari price list, but I can't seem to find it now. IIRC, Pong was about an $800 purchase. I know that Asteroids cost just under $800 to make, but I can't find what a first tier dealer would pay (and it is important to remember that there was lots of wheeling and dealing were going on -- what cost $1000 from Dealer A might cost $2000 from Dealer B).
I recall folks saying, during the heyday, that games could be paid off within a few weeks and that, as the crash neared, the life cycle of games shortened drastically making them difficult to pay off (hence, the crash). I'll need to watch the documentaries again to get a better handle.