From Chengdu to Shanghai, you can choose to take the high-speed train and the plane. Here are some possible prices and steps:

1. Take the high-speed train to Chongqing first, and then buy an air ticket from Chongqing to Shanghai. The price is around 450 yuan.

2. Buy air tickets directly from Chengdu to Shanghai, and the general price is around 670 yuan.

3. Buy the train ticket from Chengdu to Shanghai directly, and the normal fare is around 430 yuan.

The above information is for reference only, and the specific price may change due to the time, season and ticketing platform. Before buying, please be sure to check the ticket prices and booking policies of the relevant platforms, so as to choose the most suitable and economical mode of transportation.