Cheapest MS Office 2003 treachers edition..?

The elderly neighbor's new HP notebook just popped up "office trial period is over"... I'm the one she calls to solve her every computer glitch, like when she deletes whole softwares by accident, or accidentally dumps all her inbox emails into the trash, or when there's a spine-chilling virus warning pop-up on the screen, my phone rings... I guess some of you know the feeling...

So where do I get the best deal on "MS office 2003 teachers edition"?..