Adorama via eBay offers the Canon Speedlite 270EX Flash, model no. 5247B002, for $124.99 with free shipping. That's the lowest total price we could find by $20. Features include 2-step coverage for 28mm and 50mm focal lengths, bounce function, optimized recycling time, and more. It's compatible with the EOS 5D Mark II and later. It's also compatible via a firmware update for the EOS-1Ds Mark III, EOS-1D Mark III, EOS 40D, EOS 50D, and EOS Rebel XS.