That is false for just about every category of product. Look up the Amazon price and then look for a lower price and you will likely find one. The convenience of Amazon Prime keeps customers as well as the fact that Amazon advertises for many other retailers.
The shipping side of this ultimately comes through in the pricing for Amazon. Even if they offer “free shipping” to their customers, the reality is that the cost of delivering something to your door has to be folded into Amazon’s cost of doing business.