How do I buy the new cards from the Waifu House store? I see a little green cart symbol but clicking on the picture only makes it larger.
No, only if you used the cheat to open the entire gallery. But then you will also have the scene with the seller open. If you did not use the cheat, then maybe there was a bug, and they opened. In that case, you can send your last save and the persistent file to me in a private message on Discord, and I will manually close these cards for you.