Barcelona is a city that allows mobility in a great way. You can either walk around or use the efficient public transport system. The tickets are integrated, therefore you will be able to use all public transport with the same ticket and even shift from metro to bus or the other way, or from metro to another metro line for an hour and a half without paying twice. Fares can be found here in the metro fares site and all the information and routes of all the public transport through the metro site.
The way to your best stay! 