One surfer asked me how much a $2.50 milkshake would have cost back in 1958. Well, after I shuddered at the thought of paying $2.50 for a milkshake, I went to find the CPI data sitting on the Labor Bureau's web site. And I thought this was kind of neat so I whipped up a little calculator to compare prices over the years using the government's statistics (hey, you paid for them!)