For transfers from train to hotel, and so on, how much is right for a tip? We are not paying separately for the transfers, so i can't give a percent of it.
You can always search this site for I think it is called frequently asked questions, type in subject and will find answers to some of your general questions, such as tipping. Sorry, it is at bottom of screen and called search our site.
If the driver is pleasant and helps you with the bags, then a euro or two would be sufficient.