don't rent at the airport! they rip you off

I am planning to fly to calgary in august and visit the rockies(banff&jasper) as well.  At first, i made a reservation for a rental car at the calgary international airport.  It costed me $476 for 6 days, but later, when i did some digging, i found out that you can actually rent the same car for less than half of the price if you rent the car elsewhere.  I ended up paying $230 for a 6 days rental car.
here is the link of the car rental:
http://www.budget.com/budgetWeb/locationsearch/location.ex?city=Calgary&countryCode=CA