It is a "Hohner 3100GB Panther Diatonic Button Accordion key of G"
(Which is a 3 row).
Dang, you'd really need to play it to determine quality :-(
And, to determine if it is an appropriate instrument for you.
I have not played one, so I really cannot comment.
I've tried "budget" 3-rows in music stores, and they're made from
mostly plastic. If that doesn't bother you, you may be OK with it.
Probably the most serious issue is if the reeds are any good and that
they "voice" consistently from reed to reed. And, that the bellows
isn't leaky or spongy.
That's odd -- the accordion I was talking about was THIS one http://www.ebay.com/itm/HOHNER-DIATONIC-VIENNA-BUTTON-CAJUN-ACCORDION-KEY-C-w-PLAY-BOOK-HA114-/380892478269?_trksid=p2054897.l4275