Amazon has Jif Natural Crunchy Peanut Butter Spread, 18-Ounce (Pack of 6) for $11.43 (or $1.90 per jar). This will ship for FREE with Super Saver Shipping and $25 purchase.
Can you get peanut butter cheaper? Yes.
However, coupons and sales for JIF are few and far between, especially for the Natural Peanut Butter. So this is a decent price and it comes to your door.