Jingle Wall
Most wallpapers in Animal Crossing: New Horizons tend to go for about 100,00 bells on the open market. Some of the more popular/special ones may sell for as high as 600,000.
Then you have the Jingle Wall. This Christmas-themed wallpaper currently goes for 3,000,000 bells via fan markets. Currently only available via certain regions (or time skip cheaters), this wallpaper is so rare that we can’t even find a quality in-game photo of it. However, it appears to resemble some of the previous versions of this same design.
Generally speaking, any holiday items are currently selling for a ton of bells, but this is a fascinating case of a specific item that has really blown up the market.
The Gulliver Monuments
Play Animal Crossing: New Horizons long enough, and you’ll run across a sailor named Gulliver who has washed up on your shore. Help him out, and he’ll send an item to your home the next day. These items can only be acquired from Gulliver, and Gulliver can appear as infrequently as once every couple of weeks.
While that makes all Gulliver items among the rarest in the game, the highest prices are currently reserved for the monuments he offers. From Stonehenge to the Statue of Liberty, you can expect to pay up to 3,000,000 bells for some of these Animal Crossing recreations of real-life monuments.