I don’t think $7 is a particularly hefty fee. If it’s a grocery store they typically aren’t paying employees to do shop for you, it’s an extra service for an extra charge. I think I pay $10 per order from my local grocery.

I prefer to do mine on the grill with a few pieces of a louisville slugger Maplewood bat on the coals. Instead of 12 hours though I wrap mine in foil at about 7 hours when it hits the stall.