It depends. You can never get anything for spot price, with the exception of maybe pre-64 US currency. But you will get lower price if you sell it.
For generic rounds, I would say $1 over spot is average. For more desirable coinage like Silver Eagle or Maple, you have about $2 premium over spot per coin. I like some kind of gov issue silver coinage vs. generic rounds. You pay more but you get a higher resale value and they are easier to recognize. I think Joe Six Pack will feel safer given the coin has "1 dollar" stamped on it.
The best prices I have seen are on tulving.com. But he does require a substantial minimum purchase like 20 oz in gold and something similar in silver. Other than that, try Ebay. I have a local dealer who has a reasonable premium.
I think my favorite coins is Canadian Olympic silver from 1976. They are in plastic capsules and usually mint. They are 925 fine vs. 999 so that means they are more suitable for circulation (999 stuff is too soft) The best thing is, you can usually get them for spot price. Historically, silver in currency has always been about 900 fine to 916 fine, it has copper added for durability. These Silver Eagles would get beat up pretty badly if you carried them on a daily basis.
http://www.liveauctioneers.com/item/5135417Lastly, I think in this bull market silver will outperform gold but both are pretty good choices.