I don't know what you mean by coins - do you mean coins as in old silver coins that are hard to find but in coin shops or coins as in Silver Maple or Silver Eagle. If latter than IMO you're mistaken. In Canada, silver eagles have a value of $5 on that back if I remember correctly and I don't know what the silver eagles have stamped on them. I can't say for US bullion coins so I won't but here in Canada all CANADIAN bullion is tax free to buy so you don't pay any provincial or federal taxes BUT if you buy foreign bullion you PAY tax! Also you have to look around for best deals because premiums vary from place to place - and banks usually sell for most, Also Canadian bullion is one of the purest in the world. Regular gold maples have a pureness of .9999% and the new gold maples released last year for sale have pureness of .99999% that's as high as it get at present.
If you're from Canada and live in the west I can tell you who sells bullion for the best price. Also in Canada any sale over $10,000 requires government notification which is something you should keep in mind. Another thing is - more you buy, cheaper it gets. Usually premium drops when you buy 100oz and then at 1000oz.
Also one other thing to consider is where you're going to keep it. If you keep it in safety deposit know you're laws and right to your holdings if something happens to the bank or country in case of major crises - basically - can the government confiscate contents of safety deposits? To my understanding patriot act has something vague in there that you should read over carefully if you live in states. If you keep it at home read over your insurance policy as to what is covered and to what extend.
One last thing to consider depending how much you're buying or holding is in case of emergency how quickly get you get it and what is easier to take with you gold bullion or silver - example 10oz of gold or 500oz of silver.
Basically if you're buying bullion as a hedge in case of some sort of crises you have to consider the worst case scenario when this bullion would come in hand. Oh one last thing to consider is what would be easier to barter or sell - bullion coins, rounds, wafers or bars.
Hopefully I covered everything about buying bullion in Canada and didn't come off like a total nut case lol