SanDisk.com has 256GB SanDisk Ultra Dual Drive m3.0 OTG Flash Drive (Bulk Packaging, 54-99-13534-256G) on sale for $59.99 – $6 w/ promo code UltraDualSD = $53.99. Shipping is free.
Features a micro-USB connector on one end and a USB 3.0 connector on the other.