Resurrecting an old thread I know, but interesting. I thought "I NEVER get this lucky" then I started thinking about it. I've been pretty lucky with some of my finds over the years. I look at it as, out of my 12 current games (4 cocktails, 7 uprights, 1 pinball) and a jukebox, I paid retail for my GT Complete and the rest were free.
Mine:
Working Donkey Kong - $50
Centipede - $50 (just needed a bridge rectifier)
Lot of 15 games - $1500 (sold UMK3 and 1 of 2 Rev X's and made over half my money back, sold a few more then traded the rest for a Golden Tee Complete).
BurgerTime - $100 (needed $5 in caps)
TMNT - $60 (could have had a Ms Pac and a Playchoice 10 for an extra $150 but didn't have room to haul them in my Rav4

)
Working red Donkey Kong - $250
Golden Tee 98 - $100 (that might not seem like such a good deal, but I traded it later for a *nice* Stellar Wars I found on CL)
Dig Dug cocktail - traded a couple of Nintendo boards that I had left over after projects (works and looks nice, just needs glass and underlay)
Pole Position and a *nice* Donkey Kong cocktail - traded a multicade project I was working on straight up.
Super Pac-Man - $100 (just needed a cap kit)