Is it expensive to rent a small duplex in Shanghai for 2000 yuan?

Not expensive. The rental market in Shanghai is relatively high. Generally speaking, the rent in the central area of Shanghai is relatively high. You can only rent a small single room for 2000 yuan, and the rent in areas far from the city center is relatively low, but it will not be much lower. So renting a small duplex in Shanghai for 2000 yuan is not expensive.