fixing a busted light on a buick?

i hit a foreign object on the interstate the other day and it busted my left headlights. my brights are fine but the dim side glass is broken and the bulb is out. is there a way to replace it without breaking the bank? i was told something about sarran wrap or celephane (sp?) and just replace the bulb. and i heard that was legal. i have an 89 buick park ave electra. help!!!