It looks like something just hit it, or it's a die chip. It gives no extra value. Your dime is worth about a buck.
Just bought a Walker short set recently. Thought it was a nice well matched set and thought that the old PCGS holders were cool too. The display case they are all in is pretty sweet as well.
The cheapest gold coin I can think of is the dos pesos coin. Will cost you around $50.00 and shipping costs if you get one off the bay. good luck saving up some ducats :thumb: