Not only do they provide fruit, but you’ll also be able to source essential DIY materials from them. Swing your ax at a trunk to find different types of wood that are used to craft items but can also be sold. Alternatively, simply give a tree a shake. Shaking trees that bear no fruit is always a gamble, but sometimes items you can sell will drop down from the branches. Additionally, dotted across the island are several trees that randomly contain Bells. Shaking trees for money isn’t the fastest way to top up your Bell balance or the safest, but if you’ve exhausted all other options shaking trees is worth a go. Whack a rock with your shovel or an ax and it will produce smaller rocks, ore like iron nuggets and clay. These items can all be used in crafting or be sold for small amounts of Bells. On rare occasions, you may even find a gold nugget that can be sold for lots of Bells from https://www.acbellsbuy.com/
Each day a new rock on your island will be designated as the money rock. Finding it can result in you boosting your balance by a massive 8,000 Bells. To collect the bounties that this special rock offers, you’ll need to stand close by and continuously strike the stone until there are no more bags of Bells to collect. You need to get a rhythm going to maximize Bell production, so be careful not to miss a hit or you’ll break the money chain. Fortunately, there's the old rock trick from previous games that works just as well in New Horizons and guarantees getting maximum resources from bashing rocks - give it a try.
Weeds on your island signal neglect and, for many players, their first act in the game will be de-weeding their island. Once you’ve collected a load of weeds you’ll be left with clumps of weeds in your inventory made up of 99 individual plants. Take these to the shop and you’ll be able to bring in 990 bells for each clump of 99. While this isn’t a huge profit, you’ll be able to kill two birds with one stone by cleaning up your island and earning some Bells while you do it. As suggested in the comments, later in the game you'll have the option to craft weeds into Hay beds which will not only sell for more but also nets you, Nook Miles, for the crafting.Buy Animal Crossing Bells