BuyDig offers the Canon Speedlite 580EX II Flash, model no. 1946B002, for $449. Coupon code "cn580ex" cuts it to $429. With free shipping, that's the lowest total price we could find by $20, although it was $56 less last December (since expired). This hot shoe flash features an AF assist beam, 14 custom functions, dust- and water-resistant build, PC sync port, and more.