Little-known fact: Thanks to Colorado's complicated and unusual taxi laws, our cab companies can charge different meter rates, something that's impossible in most U.S. locales. Here's how those different rates stack up in Denver: Metro Taxi and Yellow Cab charge an estimated $2.25 a mile, while Union Cab clocks in at $2. Freedom Cabs, however, prides itself as being the cheapest of the bunch, at $1.80 per mile. So call Freedom the next time you need a ride: Those purple cabs could save you some green.