For Shop Your Way Rewards members only, Kmart offers the Essential Home Belmont Twin Bunk Bed in Black for $161.10. (Not a member? It's free to sign up.) Coupon code "SAVEATK5" cuts it to $156.10. Opt for free in-store pickup to avoid the $99 shipping charge. That's $44 off list price and the lowest price we could find. It features a supplemental rail and can be converted into two twin size beds.
Of note, Shop Your Way Rewards members will earn a Kmart credit with this purchase and may be eligible for additional credits and discounts.