I did the math and decided pennies would cost less than a lot of other flooring.
I did not want to crawl around on the floor any more that I had to so I organized the pennies in a cookie sheet. I stuck them to a piece of contact plastic and made me some tile like squares.
I got my husband's rolling stool he uses to work on cars, and went backing and forth gluing down the "tiles".
I used a level and piece of board to hold the pennies tight while the glue set up enough to keep them in place. I learned this the hard way. Otherwise the pennies tended to float and spread out were I would have to cut pennies to fit. NOT fun. I tried to grout but with my tight pattern, nothing to grout. Three coats of poly and done. 3 months and $300 bucks later. Just for the pennies, then there was glue, contact plastic, and poly.