Kmart has the Totes Clear Bubble Umbrella in Primary Dot for $15.99. Opt for in-store pickup to dodge the $5.75 shipping charge. That's the lowest price we could find by $10, excluding the mention below. It features a 52" arc.

Note: It's also available at Macy's in Clear or Primary Dot for $18.20 via coupon code "FRIEND." Choose free in-store pickup; otherwise shipping is free with the purchase of a beauty item. (They start at $4.) Deal ends May 7.