Went back to Wild World for the purposes of catalogue completion. Then I looked up how to get the town hall model and my heart sank. How did Nintendo expect anybody to ever legitimately acquire this?
Yeah, anyone who thinks the gold badges in New Leaf are ridiculous should try to complete the catalog in the older games! 999,999,999 bells for the town hall model in Wild World, or the post office model on GameCube, or the ADB in City Folk. Completely insane. This is why I'm not even trying for a full catalog. It would require very frequent play for decades. I'll be lucky if I ever save up 100 million bells in the old games, but a billion? Forget about it.
I calculated, and even with using the interest trick, which I think is the fastest way of making money in WW, you'd have to do it approximately 10,000 times.