On the UAA homepage, at the very bottom, is a link to uaonline...you can create an account with your brand new student id (but if you JUST registered, wait a few days for the paperwork to be inputted) and you can pay invoices there. BTW, I work at UAA which is why I asked...! ; )
I love our automated registration and payment system because I can't stand having to find a place to park (my office is off campus, thank goodness!)
And for all of you considering or wishing to go back to school - there is so much available online these days that the "classroom full of young kids" is almost a thing of the past.