Primers! If nothing else I already stocked up on lead. And if push comes to shove.... I would go bug nagantguy to swap me a couple hundred of my primers for some of his lead. Odd that this poll should come up now. I'm down about $60 worth of primers but that is because I bought 175# of lead, which required my raiding the stash piggy bank. It was there, I was there, it smelled good and tasted better so it went home with me.
I'm 110% in agreement with the post on buying a bit more than you use every month, or setting aside funds for an order or purchase in bulk. If you spend a few months and even years buying, swapping or scrounging more than you use eventually you build up a stash. Need 2 then buy 3 until you reach a level that makes you feel comfortable with your stock on hand. Trick is to try and avoid the temptation to buy another mold in a caliber you can already cast for, or additional equipment or tools to enhance your reloading bench in ways that are worthwhile but not really necessary. Or like some might do buy 175# of lead because you find printers lead you buy printers lead right?