These copper coins from the Bengal Presidency era in India (late 1700s and early 1800s) are somewhat common. An Internet search for 'Coin Bengal Presidency' yields a plethora of images, many with the characteristics of the coin in our picture. Jeff sent us a picture of his coin which, we believe, is a two pice. The half and one pice coins look very similar.
Value-wise, condition or state of preservation is the most important factor -- more important than date or denomination. A well-preserved coin like the one in our picture can retail for over $100 US dollars. Jeff's coin in our secondary picture, much more worn and corroded, would be down in the $10 to $20 range.
As always, dealers in such material need a good mark-up to maintain their businesses. Figure if a coin would retail for X dollars, and dealer might offer one-half X to buy it from you.