I go to a music school and my singing teacher is just AMAZING. She teaches piano, guitar and singing.
Her voice is nice but most importantly for me, she picks up every song i choose and plays it in the piano effortless, even if she hasn't listened to it before. Then she tells me where to breathe, how, etc...i dont know, i love my lessons with her.
School charges 70CHF per hour and then has offers, per half hour, per month, per year, per 10 times....
I hope this gives you a guideline.

good luck!