I did a full rebuild on a 2001 polaris sportsman 500 and it came out to $500 after everything. They are not hard but can take time. Let me look around cause I might still have a book for it. YouTube can definitely be your friend. Would be a good project to do with your kids.

The first requisite of a good citizen in this republic of ours is that he shall be able and willing to pull his own weight.
Theodore Roosevelt