About $3 each.
They are exactly the same plant. When I first purchased 40+ types of willows for BRT, I noticed "Dappled Willow" (the simple name I tend to use) had some qualities that were useful for deer guys. So I started growing it in bulk and selling them at a lower price.
To be fair, the ones you find at the garden store are established plants in a pot. Not a cutting, so the price difference is reasonable.
-John