Okay, please learn from my folly:
Step 1: I ignored Brickseek, because it didn't correlate in any way with the Target website.
Step 2: I ignored the Target website, because it didn't correlate with the phone calls I made to Target.
Step 3: I called about 6 stores in my area to check on stock, and they authoritatively told me that no one had any Weber charcoal in stock. Except for one store, who said they had only two bags which they would hold them for me.
Step 4: Showed up at the store today, collected my two bags, and just for grins I headed to the back corner of the store (aka, clearance area). Where I found four more bags.
Step 5: Just for grins, I stopped at another Target on my way home, where I found six more bags (remember that they previously said they had zero).
Lesson: Target has no earthly idea of their inventory. I let my fingers do the walking, but that was dumb. I should have just driven to the goshdarn stores.
FWIW, everything I saw today was priced at $9.98. Kinda bummed to miss out on the super-bargain $7 stuff, but I think I'm more glad to be done driving around with three kids and stuffing 20lb bags of charcoal under their feet in the back seat.