In Romania the law requires all retailers to display the maximum price markup they have. Dutifully every single retailer displays the same notice "This store practices price markups between 0 and 300%" (over 300% notices exists, but are rare).
Wow, 300% is low for maximum markup in the US. Small clothing stores, for example, have approximately a 1000% markup. I worked at one such store, and the store only turned a profit in November and December (due to rent being so high).