Shanghai is China's main port and the city is sports various cruise liners, large-style mega-cruisers and smaller yachts. Some of the ebst cruise delass in shanghai are:
Royal Caribbean’s Legend of the Seas (Shanghai, Bangkok, Singapore)
Costa Cruise's Costa Classica (Nagasaki and Tokyo)
Princess Cruise's Ocean Princess (Shanghai cruises with Singapore, Beijing, Ko Samui, Seychelles and Cape Town)
Regent Seven’s Seas Voyager Shanghai, Ho Chi Minh City, Singapore, Phuket, Mumbai and Dubai and trips till Suez Canal, Istanbul, Rome, Barcelona and Fort Lauderdale)
Seabourn Spirit (Shanghai, the Indian Ocean, the Red Sea and the Mediterranean, with ports of Sharm el Sheikh, Marmaris and Mykonos)
Smaller cruise lines offering Shanghai cruises include Silversea, with the Silver Whisper sailing to Hiroshima and Kobe.
Some cheap travel agents are;
China Spring Tour
SISU Cycling Club
Gaia Trips
Red.Travel
Waterlines
UnTour Shanghai
Shanghai Outing Club
YANA Adventures
Newman Tours
Ctrip
ABA Online Hotel Booking
Big Blue Scuba
And subsequently there are many more