in
viewtopic.php?t=934 d_m_kolb posted a link to this
2003 Matrix Parts Catalog
and it lists the Toyota part numbers for a 2003 Matrix fuel tank stuff on 16 of the PDF. If the part you are looking for is "11 Hose, Breather" then for a FWD vibe, the Toyota part number is 77269-02020, and a quick google shows amazon and some Toyota dealers have it for 15-25 US $
I would fully expect the matrix part to be the same for an 03 Vibe, but if you do buy one and its not the same, well, don't come after me for the money
And Welcome to GenVibe!
The forum software has a limit on uploaded file size, so its likely you'd need to rescale/resize the pic to be a smaller file size to get it to upload