The bullet train from Guangzhou to Shenzhen leaves from Guangzhou East railway station, and the ticket fare is first class CNY100 and second class CNY80. You have to tell me what you will buy first, and then I can check the cheap whosale market for you. In retail market, there is no limit for the amount you should buy.
From Shenzhen to Parklane hotel Hk, you can go through Luohu port to take Hk MTR east rail line to Hung Hom of Hk, and then take bus no. 118, 103, 106, 102, 116, 117, 108, 112, 107 to Cannon Street near Cannon Street, adn then walk to the hotel. It's possible from Shanghai to Guangzhou Buy train, which takes about 16 hours.