So, I ran back into Publix today to see if they had restocked the peanut butter...and they did! The 40 oz jar was on sale BOGO for $5.49 (so 2 for $5.49). I had 2 $1.50/4 coupons and one $1/2 coupon, so I bought 10 jars total.
Even without coupons it ends up being less than $0.07/ounce, which is better than the last time I stocked up on peanut butter (which we are now out of). You can imagine the comments I got buying 10 huge jars of peanut butter, but I guarantee this will be gone by the end of the year (at the latest....and it doesn't expire until November 2011).