On a quick business trip I always do two things - look to see if any interesting models live in the city I am visiting and see if there are any used camera shops I really should acquaint myself with.
Shanghai is no cheaper than UK discounters for everyday d*g*t*l offerings from the usual suspects - or they didn't appear to be; I have no interest in the exact pricing of the latest mega-pixel offerings from the usual suspects. But the second hand market is very interesting. There is a cluster of tall buildings (5 or 6 storeys) at 300 Luban Lu in Luwan. Find building C and take the lift to the top floor. Keeping your wallet within easy reach, walk down to the ground floor. A disposable tissue might usefully be kept to hand to administer to frequent droolings.
Many classic cameras are for sale, across 10-20 different shops per floor. Prices are similar, or slightly less than UK FleaBay prices, but the selection! I saw limited editions of models I didn't know existed. I saw cameras and formats I didn't know existed. Some in mint condition, others which looked as though they had covered the London-Peking car rally, in both directions, mounted on the car's roof, but all priced appropriately. I don't know if they were open to negotiation on pricing as I, somehow, managed to emerge into the daylight with my wallet still firmly intact (flying hand luggage-only and returning to London via Moscow and Zurich rather limits the acquisition of a new LF rig).
Just two things to note - at 1100 on Saturday morning, many of the stores were closed. I think this may primarily be a Monday-Friday market. But if you are in Shanghai mid-week with an hour or two to spare, building C is as good a place as any to spend some time. The cafe on the ground floor of the adjacent building is to be avoided though - the worst coffee in all of China, let alone Shanghai.
Good hunting!