You can try ebay, sometimes there are deals. Call you local coin dealers, they usually carry bullion. Gold bullion has a premium above the spot price attached to it, smaller quantity have higher premium (1/2, 1/4, etc) waffers have smaller premium than coins. There really isn't much advantage one over the other IMO, but I like bullion coins more, if need be and I have to pass it to my kids coins might be worth more, people like the look of coins more than waffers. If you buy online think of the cost of shipping because might be cheaper to buy it at local coin dealer. Gold Eagle isn't pure gold and gold buffalo is. Gold is easier to store than gold (quantity wise). I think that's all I can say for someone that's first buying bullion. I think the only other thing to also look into is if you store your bullion at a bank or any other institution how US laws can affect you (ei. Patriot Act).
I like colorado gold and Don is a real straight guy and very honest. My personal choice is all since you asked. I also like Krugerrands due to low premium here and sell the same in Europe as Eagles or Maples. The nice thing about Eagles is the "face value" is so low and the US Customs counts gold coins at face value when you move them out of the US should you ever wish to do so.