Check out this thread…The Sandcast Thread Towards the beginning there’s a really good article on the difference. Hopefully that will help!
I don’t have any way of giving you an idea of what the cost might be from a store, because everything varies so much, and prices can be higher in stores, because of many reasons like overhead (plus you’re more likely to get accurate info about a piece from a good store). If it’s sterling silver and Navajo, I would think $300 is a good price.