Gold nuggets are neat! However you have to understand that size and purity all matter in trying to determine the price. Likewise crystalline gold will command a premium as well.
Nuggets from Australia for instance are more pure than Alaska, It is not as simple as taking the gold price and dividing by the number of grams to determine the value.
You might want to look at the auctions on eBay from chickenminer and or go to his website
http://www.chickenminer.com/. He is a full time miner who lives in Chicken, Alaska! I've purchased gold from him in the past and he is always great to deal with.
The bigger the mesh number the smaller the size of the flakes or nuggets:
http://www177.pair.com/nugget5/goldsizechart.jpgMost of the time you can get gold dust and flakes much cheaper than nuggets. But beware some on eBay will quote grains versus grams or not be upfront and use a millimeter ruler versus show one that has inches.
Gold in any form is good to have! I hope this helps a little....