My friend married some jerk and now she wants a divorce. How much will it cost her?

She's known the guy for 10+ years and she believed that he was her soulmate. She married him about 5-7 months ago. She caught him in their bed with two other women. I think thats a good reason enough for a divorce right? I heard you can get an annulment too, but I'm not really understanding all the legalities of it. What advice would you give her? I told her to seek a lawyer.