You can certainly present the same price of the good to every user, while also automatically calculating the cost to ship to their postal code--if they specify

You can certainly present the same price of the good to every user, while also automatically calculating the cost to ship to their postal code--if they specify it, or the postal code most likely for their IP address if not. Then apply a "combined shipping discount" calculation when they go to view the contents of their shopping cart, for everything that can fit in a single box shipped from a single warehouse. Then allow the user to sort on base retail price or price plus shipping, as they prefer. Being transparent about goods versus shipping makes the customer feel better about not getting manipulated and/or ripped off.