Magicians are known to have tricks with gimmicks and I think that when you borrow something and then go and have it signed, the spectator doesnt think you could switch out the coin....
I prefer Scotch and Soda becuase sometimes you get a person thinking you could easily have another dime or penny palmed because they are so small..with scotch and soda, people dont always think you could have an extra coin. Just my opinion though.
I believe you can get a very very similar version on penguin magic called the Daley Show for dirt cheap. http://www.penguinmagic.com/product.php?ID=631 thats the link for ya
Check out the trilogy...a lot of those tricks require zero setup and if there is setup, its nothing you cant do walking down the street or infront of the spectators.
I like to use this Patter: " Okay now I am going to show you something along the lines of hypnosis...I am going to make you see things that arent real. Here pick a card....etc. then act disappointed when you find the 4 and then," Okay I will show you what i was talking about. I want you to...