When you offer free shipping, and your competitors do as well, your USP is not unique. I see this very often: businesses don’t compare their USP’s with competitors.

Your visitors certainly will compare you with your competitors. If you offer the same benefits, you’re not really unique.

Emphasise your unique differentiators, those that others don’t mention and, ideally, something they can’t compete with.

But.. I don’t have a unique USP!

Well, a great way is introducing a new benefit others don’t mention.