Yes, you can take train to Guangzhou and Yiwu from Shanghai, trains to Yiwu would costs around CNY50-100, run about 3-5 hours for different trains. trains to Guangzhou costs around CNY300-500 for about 20 hours. Yiwu is the best place for small goods while Guangzhou is famous for its clothes markets, accessories markets and some special produce place for other things in places around Guangzhou.