Years ago I flew into Vegas thru the Hughes terminal. I got back there two hours early for the trip home so I decided to play a few nickel machines. The bank had like 5 machines in it and the middle one was buzzing and whirring. I avoided it but lost money on the other machines and finally decided to give it a try. I put in a nickel and was given credit for two coins. Next time I put in two coins and was given credit for three coins. Hmmmmmmmmm. Since there was no bonus for more coins I played the machine with one coin in for 1 1/2 hours until my arm felt like it was going to fall off from pulling the handle. When I cashed out I had a pile of nickels big enough to fill two or there coin cups. The math is even if the machine only paid out 70%, which was possible in those days, I was getting credit for 200% or making a net profit of at least 40% payout.