Go to the concert yourself
- Bus (Warszawa - Riga - Warszawa) = 86€
- Taxi (Station - Concert - Station) = 20€
- Hotel (Most likely you will need a hotel, because the first regular bus leaves at 6 am, and the concert ends at 00:00) = from 70 € (If there are free apartments)
- Time and nerves spent on planning = priceless!