Free lunchtime concerts (from 1230pm-1pm) at the Boekmanzaal every Tuesday from October to June.
City Hall / Stopera Muziektheater, Amstel 3

The Concertgebouw offers a free concert every Wednesday from 1230pm-1pm. Often these concerts are rehearsals in front of public audiences by orchestras such as the Royal Concertgebouw Orchestra, performing "officially" that evening.
Concertgebouw, Concertgebouwplein 2-6

Free ferry rides across the IJ. The IJ separates downtown Amsterdam and Amsterdam-North. This is the oldest part of the Amsterdam harbor. It is a cove of the former Zuyderzee, now the IJsselmeer lake. You can cross the IJ free of charge by ferry.
The 'Java Ferry' travels to the north of the Java Island from jetty 8. Java Island is one of the 'new' islands in the Eastern Docklands/Harbor area. In a short period of time this area has developed into a must-see attraction for people who like eye-catching, modern architecture. The ferry takes you to the north of Java Island in approximately 10 minutes. From here you can also go to KNSM Island, Sporenburg and Borneo Island.

Visit www.trippist.com for more local & budget info on Amsterdam.