WTB: Eagle 320 or 480DF - looking for best delivered price

After giving it a lot of thought, I have decided to get either
the Eagle 320, 480 or the 480DF fishfinder. I'm leaning to
the dual frequency 480DF, but not 100% sure it will help me in
shallow (3' 30') water? But it just looks to me like the 480DF is a
lot more powerful - for a little more cost. If it's not that much
better in shallow water, then I'll go the cheaper 320.

I'm shopping for the best "delivered" price to TX. If you have
seen a sale, please advise. I think I'll install the new Eagle as the
main fishfinder, and an old used Hummingbird as a backup.

Gene