How much Juvederm would I need for my smile lines? And how much would it cost? (Photos)

Hi, you ask a great question. The smile lines you're referring to are called nasolabial folds.  Those are a normal feature of your anatomy.  Based on your pics, permanent creases have not yet formed, so you're a great candidate for fillers.  I think you could be treated with 1 or 2 syringes. Generally the cost is $500-$600 per syringe. This treatment is typically done twice a year.  Seek out an experienced injector and stick with them. Establishing a good relationship is key to successful cosmetic procedures. Good luck!

A combination approach is needed to get the most improvement for smile lines and this often means fillers for the lines themselves but also lifting around the mouth and cheeks to build underlying anatomical support. In our practice we combine sculptra with other fillers "layered" on top and lasers, rf treatments and peels to get the most conservative natural look. Please see a facial sculpting expert. Best, Dr. Emer

None of the photographs you submitted show a smile, so it is difficult to comment. Consider posting some photos showing smiles.

Given your youth, I doubt that you would need more than 1-2 syringes. The cost is going to depend on which filler is used, where you live and who you see. However, keep in mind that a good aesthetic outcome is completely dependent on the skill or your injector so you want to see someone who is very experienced like a board certified plastic surgeon. 

Honestly, I prefer the newer flexible gel hyaluronic acid fillers like Restylane Refyne and Restylane Defyne over Juvederm for the laugh lines (nasolabial folds, marionette lines) as they provide a very natural looking result because the flexibility of the filler preserves normal facial expression. You could also  benefit from filler injection to the pre jowl and chin but I would use a slightly thicker filler for this indication such as Restylane-L, Radiesse (+) or Juvederm UltraPlus.