The PLCB (Pennsylvania Liquor Control Board) does not regulate prices for malt and brewed beverages. But a quick online search says it costs around $15.00. It is a popular beer choice among college-aged individuals, due to its relatively low price.
Your best bet would be to locate any beer distributor in PA via an internet search and to call and inquire about the cost of Keystone Light. Or, if you are located in PA, just stop in a local distributor to check that way.
Keystone Light was first introduced in 1989 in Chico, California and is a product of the Coors Brewing Company. The fictitious character, Keith Stone, has become the pop-culture iconic promoter and has appeared in numerous television advertisements. These advertisements have inspired many customers to make online spoof ads.
Check out tips for drinking responsibly from ReachOut.com.