Around $8k for my 28 game collection, and that is without profit as I've never sold/resold any games or parts. Due to my low teenage budget I was (and still am) pretty forced to rely on great deals for games which is probably a blessing in disguise. Never paid over $500 for a single game and that price was only once (Williams Comet, last year, working and nice).

At the point now where I semi-frequently end up directly rejecting or passing up good deals because of space and all that. They truly do start flowing to you once you're "in" the hobby.

I've theoretically thought of what I would do with the giant heap of money if I sold all of my machines and I honestly couldn't find much of an answer, because when I get money I usually just buy more pinball machines... I definitely love it.