As of March 2015, the fee for excess baggage on Alaska Airlines, defined as the fourth bag for all fare types, is $75. An exception is for military personnel and their dependents, who can check up to five bags for free before being charged $75 per bag.
On Alaska Airlines, most fare types can check two bags for free. Those flying within the state of Alaska can check three bags for free. Standard fare passengers are charged $25 per bag for the first two bags, and $75 per bag for each additional bag. All bags checked, regardless of fare type, must weigh less than 50 pounds and measure no more than 62 linear inches.