My stockpile is running well. This week, I spent about $40 on groceries because I had everything I needed in my pantry already. Including meat. It was a nice feeling. I'm waiting for a good price to stock up on Ziploc bags before I run out.
When you go into your stockpile for something, check and make sure that you aren't close to running out. If you are, write it down on a notepad, and, looking through the flyers/online sales, etc., keep your eye out for the lowest price around. If you've done a pricebook and know what the lowest price is, it should be going back to that price soon. If you can hold out buying it until it reaches that price (and if you run out, try and improvise with other things), you'll be maximizing your spending plan.
This is my weekly list, usually:
Sandwich Bread/Whole Wheat Rolls
One or more stockpile items I'm close to running out of, that are at their lowest price.
I rarely follow that well. But as long as I have a good stockpile, I really don't need to buy much else. It's been really neat seeing my pantry stay stocked, and my need list stay small.