Originally Posted by
FallenPlat
Not only can you purchase bag fees when you buy your ticket, but as of a few weeks ago you really have to: if you don't, the price goes up for any later purchase. I'm not sure about how the $9 thing works, however.
I never pay any fees myself, and so I'm just going by what the website says.
I tried to pre-pay a bag fee at IAH when purchasing a ticket for a flight well in the future and was told the baggage fee was $80ish.
Basically, no way to get the $5 cheaper bag at the counter like you would get if you booked online.