At Puritan's Pride, buy one bag of NOW Foods 10-oz. Almond Flour for an in-cart price of $9.40, and get a second bag for free. With free shipping, that's $4.70 per pack and the lowest total price we could find by $8. This gluten-free flour is a low-carb substitute for other flours used in baking.
A close price: PureFormulas has the same quantity for $9.85 via coupon code "NOW10".