Let's say that there are 100 pinball machines for sale in an area. 50 are priced fair, 20 are priced too high, 20 are priced to sell and 10 are priced low. A flipper will do their best to take all the great deals and price them higher. The end result is that no-one else gets good deals. They are too involved in the money and do not play and enjoy the games past the dollar values involved. Basically they are a middle man that drives prices up and usually do not provide much more of a service to the community.