The other "main" shopping road is most probably Nanjing Lu, which leaves from the Bund and is kilometres long. There you can find shopping malls after shopping malls and also Mc Donalds in every 100 metres (almost!).
Between Nanjing Lu and Huai Hai road is Shanxi road south, there you can find smaller shops selling mostly clothes and shoes. But if you are not in the area, do not bother, but it is worth a promenade if you're around.
But like in every city, it will be cheaper if you wander away from the mainstreets and look for shops in different areas. The road names I just gave are just few shopping streets in Shanghai but perhaps the most popular ones?

