GO TO A VET!
It could be a slight sprain or it could be a broken bone. Go to a vet and find out. If it's nothing you can pay a vet 40 bucks and walk out reassured that your dragon will be ok. If it's something then you will have to decide whether you can afford the operation or treatment that will follow...if you can't scrape together enough money together for the operation, you should donate your animal to an adoption agency, someone can afford to save your dragon if it is a problem so don't let it suffer. It is in the best interests of the animal.
I'm probably sounding harsh but you should have thought about costs and vet bills before you got your dragon...all of my animals are checked once a year or as soon as I think there is a problem. They are usually checked right after breeding to assure they are recovering well.
I hope you can grasp some common sense and think about saving your dragon. You should have contemplated your financial situation before investing in a fairly expensive reptile in the first place.
This is just my opinion, I could be wrong.
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Chris
1.2.0 Bearded Dragons
1.2.0 Green Basilisks
1.1.0 Crested Geckos
1.2.0 Veiled Chameleons
1.1.0 Corn Snakes
1.0.0 Tokay Geckos
0.0.1 California Kingsnakes
2.5.1 Leopard Geckos