Cost varies from place to place and clinic to clinic and experience of doctor.
Once removed, you need to brush well twice daily using soft brush, good paste and technique to minimize formation of tartar again.
Next Steps
Go to a dentist in your place and get it cleaned. it's a very simple procedure and might need 1 to 2 sittings
Health Tips
Going to a dentist for check up once or twice an year is a good practice. During the check up they will tell you if you need teeth cleaning. if you have kept it clean, they won't do cleanup. If deposits are there, they will do cleaning.
During yearly regular check up visits, any small issues will be cleared and preventive care will be given to prevent bigger problems later.