How much does it cost to service a MacBook Pro battery? I have a mid 2009 MacBook Pro and I just got a message saying that I should service my battery.

I tried to reset SMC and NVRAM but the problem persists and I fear I'll have my battery replaced. How much is Apple going to charge me?

My Mac is out of warranty and I see that the battery capacity is less than 80% than it was originally but apart from that it is working fine
See Replacing the Battery in your MacBook Pro for pricing information in various countries. In your case (Italy) it's 130 or 180€ depending on screen size.