Never sell back to a dealer, but they will buy any of your precious metals, no problem. They will give you under the spot price of the metal.
They sell at over spot price, and buy it for under spot. They aren't you ripping you off, they got to pay the bills....
Check
http://www.coinflation.com/ for the latest spot prices....
Always make sure you own the actual metal, never buy paper gold or silver futures. That's only worth the paper it's printed on...
I don't play the game, so much... I go for the long term, or at least I try to..lol