I'm not sure but I think 1 or 2 million. I have the set but I got it free from my friend who TT for them but no longer wanted them. I do like the set .
Unless you're talking about the zodiac furniture instead of the animals, in which case the furniture is reorderable DLC and two items from it have been released so far. The zodiac animals are the new year gifts.
I've seen it sold from around 1 to 4.5 million bells.
I personally don't really like it. I mean the individual pieces are cute and all, but it doesn't make much sense to break up the set, and I wouldn't really want to dedicate a whole room to displaying it. I might put it in the museum.
I think you get one piece every year - I believe you get it from Isabelle on January 1, when she's standing in the plaza. People that have the full set most likely time traveled 12 years or so to get every piece, since you're only supposed to get one piece every year.
I got them in a giveaway iirc.
I just wanted the dog one so i could have it be my pet "cat" in front of my cat-tree in my house :3 (tbf, it does look more like a cat than a dog!)