Walmart offers the Samsung 64GB Fit USB 3.0 Flash Drive for $18.25. Order via in-store pickup to drop the price to $17.54. That's a buck under last week's mention and the lowest price we could find today by $4, excluding the mention below. It's water-, shock-, magnet-, temperature-, and X-ray-proof and features data transfer speeds up to 130MB/s.
A close price: Adorama charges $18.99 with free shipping.