Styrofoam Wedding Cake. Consider a wedding reception for 150 people: 150 people x $3.50 per slice of decorated bakery cake = $525. A decorated fake cake of the same size starts as low as $110 and remains a beautiful centerpiece throughout the entire evening. Sheet cakes start as low as 16.99/48 servings. Fake cake 110.00 + sheet cakes 50.97 = total 160.97. Total savings 364.03.