Family Christian Bookstores offers select Valentine's books, with prices starting at $5 as part of their Valentine's Day Doorbuster Sale. Better yet, Get an extra 20% off via coupon code "SAVE20", lowering starting prices to $4. That's the best sale we've seen on these items from this merchant. Shipping adds $3.08, or get free shipping on orders over $35. Sales tax is added where applicable.
A best bet is Francis Chan's Crazy Love for $5 before the above coupon, $4 after. With $3.08 for shipping. That's the lowest total price we could find by $2. Sales tax is added where applicable.