There was a guy who ran a website named SHTF. He was in the Yugoslavian civil war. He said to focus on silver, because: 1) if you have a gold coin and you want to buy a chicken- guess how much that chicken now costs; and 2) If you have a dozen dimes no one really notices, but if you have a gold coin everyone talks about it.
Oh yeah, ebay is a good place to get silver coins. Just figure out what the silver content is then multiply that to the spot price and that is your max bid (remember to factor in the shipping costs). You will loose 9 out of 10 bids, but you won't pay too much.
trouble with ebay, craigslist, etc is there are fake silver coins/bullion turning up....