1.yes, there are frequet coaches from Shanghai to Ningbo. The five coach station of Shanghai have the buses. Seems the Heng Feng Lu station and Shanghai South Station have the most.
2. the ticket can be bought at the station. I heard that those stations are connected by computure together, means you can buy bus ticket of B station at A station Don't know whether the return ticket is sold.
3.the fare is arounf 90RMB per head