How long is it open? I have the nostalgic toy instructions, but I don't want to redeem it only to find out one of the items costs more than I can acquire, then have his shop close tomorrow.

His shop stays open year-round. :)

Oh. XD There was some news post a while back that made me think it was seasonal or something. Thanks!

New types of Nostalgic pets (like the new Nostalgic Feli, Chelon, and others that were released a few days ago) are typically only released during this time of year/season but the shop is open year-round for users to use to transform their pets Nostalgic.