A teenager goes into a drug store and he says to the clerk, "I want to buy 
some condoms.  How much?"   The clerk responds "I have these here... three for 
a dollar" 
Teenager: "Perfect.  I'll buy three" 
Clerk: "That will be one doller and three cents" 
 Teenager: "What's the three cents for?" 
 Clerk: "For the tax" 
 Teenager: "No, no, I want the ones that stay on by themselves..."