The bus terminal downtown is a US$25 taxi ride. However, you don't need to go downtown to catch a bus going north. Just go to the junction of the airport access road and the Northern Highway (a little less than 2 miles from the airport terminal) and flag down any non-express bus going north. You may be able to get a taxi to take you to the junction for a few dollars though the cab drivers prefer to take passengers into town. Otherwise you can hitch or go by shank's mare.
--Lan Sluder