A diamond is forever, which is good, because that's about as long as you'll be paying for it. When you go to buy a diamond engagement ring, don't expect anything close to the wholesale price. Retailers mark up diamonds between 50 and 200 percent and 100 to 400 percent for gold [source: DY Jewels]. Warning: The biggest markups typically are found at the mall where there are more overhead costs.
Wedding dresses retail for at least 100 percent more than the wholesale price and that slinky wedding night lingerie will carry a 200 or 300 percent markup, too [source: Grant]. But what really takes the cake is the cake itself. One slice of a multi-tiered, painstakingly decorated wedding cake will cost you around $15, about five times what you'd pay for a whole box of Betty Crocker cake mix [source: Grant].
The next stop in the retail markup hall of shame is the produce aisle at the grocery store.