Large Denominations

You know that age old excuse people use when they want their friend to pay for them. I'm sure you've probably tried using it yourself a couple times. For example, buying a pack of gum at the news stand you might slyly ask your friend "Can you get this for me, it's only $1.50 and I don't want to break my hundred dollar bill." This trick might work a few times on the same friend, but eventually they will catch on after the small purchases start adding up. The trick completely failed however, when my gf tried using it on me at the grocery store by saying "I don't want to break this $20 bill." Nice try Sweetie! Muah.