As far as I'm concerned the way to buy PM's is slow and steady, unless a major drop occurs.
Try to buy some each payday. That way you have a working average across your PM price. It is easier to look at that way.
When the price of silver is 50$ an ounce, and you started buying in a 12$ an ounce, that will drastically lower your average, depending on how much you are holding.
I also do not sell, unless I'm positive I can at least double what I paid. That happened last year sometime, when the price was right around 30$. I got out of about 1/3 of my holdings and doubled the money I spent on the entire "investment" (all of it, not just the 1/3).
Now, I still have 2/3 of my original "investment" and doubled my money. That way, I already made my "money" paid some debt with it and can move on. From this point, if the PM market crashes, it won't really matter to me because I already came out victorious

. I don't see it tanking though, not with the world situation where it is.
I kinda miss holding the Johnson Mathey 100 ouncer though, that sucker was heavy!
Josh