Quoted from sbmania:

I'm surprised at the people who are whining about some people being flippers. As long as games are bought and sold honestly, who cares and who has any right to complain? Whether people admit it or not 99% of the world is a capitalist economy. Meaning things of all kinds, not just pinballs but cars, houses, antiques, watches, coconuts, etc etc etc are bought and sold at market value, every day, by a willing seller and a willing buyer.
If someone sees what they perceive to be an underpriced game, runs out, buys it, brings it home, re-advertises it, and sells it to a willing buyer for an agreeable price, then where should anyone be outraged? The seller has risked his own time and money in this venture with no absolute assurance of an eventual profit, if ever. As long as the seller does not claim the game to be anything different than it actually is condition -wise, why complain?
Any why must a flipper "add value" during the deal? As long as he is not selling a non-working game as shopped or restored, why must "value" be added? The value is in having found a desirable game at a good price, dragging it out of whatever dark recess it was found in, and then offering the game to someone else who maybe does not have the time, skills, or equipment to do that himself. And the finder in my opinion is entitled to make whatever from the game that the market will bear. If that is $50 or $5000 more than he paid - so what? If I spend my whole life out digging in the dirt for diamonds and I find a really big one, should I be obligated to sell it for $100 because I didn't add any value to it? Or because someone else is sad that they didn't find it first? It's worth what it's worth and if you want to buy it, you need to pay the price.
Now if the flipper decides to shop the game, restoring everything to like new condition, adding LEDs or a color DMD perhaps, replacing broken ramps or bad backglasses - then shouldn't he also be able to put whatever price he wants on the finished product? If it sells fairly and honestly to a willing buyer, than the price was correct. If it doesn't sell, he needs to consider maybe lowering his price. But that all works itself out in the marketplace.
I get frustrated too when I see a great game at a great price on CL and immediately call only to find I am the fifteenth caller and have little or no chance of getting the game. That just means I should have worked a little harder to find the game sooner. Somebody else did! Should I be mad because I lost out in a fair contest? Should I overbid the buyer in an attempt to steal the game out from under him? Now THAT is something that really pisses ME off! If someone gets a good deal, celebrate with the buyer and resolve to look harder yourself next time. Don't try to blow up his deal out of jealousy.