Yes indeed, there is a Coin Pile Dive in Buffalo...But you may be a couple of decades late in the game!
The Coin Pile was a very popular dive site in the 70's and 80's. Many people found cool coins from the early, mid, and late 1800s. There was also hardware (spikes, chains, barshot, etc.), clay pipes, and horseshoes. It seems to be pretty well picked over.
To reach the dive site, you need a boat. The Coin Pile was halfway down the first breakwall out in Buffalo Harbor, on the Lake Erie (outside) side. To find coins or artifacts, you would pick a spot and fan the silt away. As the site was shallow, you could often stay down for quite some time (80 minutes or more)
Today, there does not seem to be much comming up, and Zebra Muscles have taken over the harbor. But Buffalo has lot of great dive sites in Lake Erie, the Niagara River, and local lakes and quarries. If you are interested in diving the area, let me know. I can reccomend a great dive shop in the area.
Take care!