Mirror look on backdrop flooring

i am trying to achieve the look of a almost silky looking, mirror-like floor for a special shoot I am doing next week.  Many have told me that plexiglass will give me that look but I checked on the price of a 4'x8' piece and it was a ridiculous amount.  Is there anything else that can be used for a black backdrop to give me the mirror look on the floor I am trying to achieve.   Thanks for the suggestions.