If gold I would buy the lowest premium fractionals I could get, which in my case would be old foreign gold coins like 20 francs, British sovereigns, etc, for 2 to 4 percent over spot and often said coins are in AU/BU shape. Sometimes dealers will sell damaged/cleaned/polished old US gold for cheap, but I don't like to buy it damaged even though it is still gold. Many dealers will ship out damaged old US gold to refiners for melting since they cannot wholesale due to its condition, so if you don't mind it you might be able to negotiate a good deal and get them to sell to you instead of sending it off. I did that before and got some for 1 percent over spot, but I hated looking at the polished coins so I never did it again.
If silver I would get the lowest premium one ounce bars/rounds I could find, which in my case would be generic rounds/bars for roughly 60 to 80 cents over spot.
I would avoid the higher premium gold/silver like AGEs and ASEs, Maples, etc. The spread is too great and when you go to sell you don't recoup that premium, even though you will get more than for generic.
For example, here you might buy a AGE one ouncer for 60 to 70 bucks over spot, but if you sell it back you get 20 to 25 over spot if you are lucky. That is not acceptable to me personally.
The key is the spread. If you buy/sell locally find out the best spread for all types of silver and gold and stick with that. Junk silver often has a good buy/sell spread in most areas too, but I prefer to buy .999 bullion since I can get generic for pretty cheap usually.
Jim