My fiancee really likes the look of the faux tin ceilings. We found some in Home Depot, but they are 20$ for each 18" x 24" pane. For a moderate sized room, this will be a LOT of money to do one ceiling! (I'm assuming they're so expensive because they are "thermoplastic" rated to be resistant to up to 200 degrees or something like that; I guess this is because they are also for use as splashguards behind the stove.)
So I figured I'd look online for other possibilities, but there are a LOT of different brands and suppliers. What should I look for (and stay away from) when choosing faux tin ceiling tiles?