For the exact maintenance and service cost, we'd request you to visit the nearest authorized service center as they would be the better person to assist you with this. Click on the below link to see the nearest authorized service centers and select your city accordingly: click here
For the availability and price, we would suggest you walk into the nearest authorized service centre as they will be the better person to assist you. You can click on the following link to see the details of the nearest service centre and selecting your city accordingly - Service centre
As of now, the brand hasn't revealed the complete details of Mercedes Benz A-Class. So we would suggest you wait for its launch and stay tuned for further updates.