A good source for good vinyl is your local sign shop.  I have a friend who owns one and can get scrap rolls in just about any color, thickness and selectivity. 

I bought from fleabay some very cheap leather punches in the 7 - 8 mil size and honed them further so that a tap with a small hammer cuts thru the vinyl and not the backing.  I mix'n and match'm up and even use them as side markers as well.