There are two methods to getting Bones in Forager, and you should pick method #2 if you are able to. If not, stick with the first method.
Getting Bones by Digging (Method #1)Before you unlock any islands with Skeletons on them, your best method is to dig them up from the ground with you shovel. You will mostly only get Sand and occasionally Coal, but every once in a while you can get lucky and get a Bone.
You should always look for cracks and crater on the ground, beause these are rare digging spots, and have a very high chance to contain a Bone or another rarer item. A lot of people report having found 3-4 Bones early in the game by digging all these spots. These cracks can be a bit difficult to see, so take a look at the screenshot below to get an idea of what they look like.
|The crack that contains a rare item (and in this case a Bone) is a few grids directly in front of the character.|
Getting Bones by killing Skeletons (Method #2)Once you unlock the Graveyard Biome, getting Bones is a piece of cake. This type of biome is located to the left of the starting island, so it can be easy to get there is you work towards it from the beginning.
On this biome you will find graveyards which you can destroy with your pickaxe. Once a graveyard is destroyed, a Skeleton will spawn, and this enemy will drop one or more Bones upon death. So just keep destroying those graveyards and kill the Skeletons, and you will have more Bones than you need very quickly.
Buy the Bones at the Market (Method #3)This final method requires a fair bit of luck, but it's definitely possible. The Market has a chance to sell any item in the game, and the Bones seem to be for sale pretty often. They only cost 4 Coins each to buy, so you can get a lot of Bones if they spawn on the Market.
I recommend just checking the Market every ten minutes and pick up all of them if they spawn. This won't be enough to upgrade all your items, but it will allow you to upgrade the most important ones.