Making a tailor made shirt can be a far better option than buying fake shirts. The price of tailor made clothing depends on the quality of the fabric and the location of the shop.
Shirts can cost everything between 120 RMB – 500 RMB, from my experience. If you go to a decent tailor at Nan Pu Da Qiao in Shanghai, for example, you shouldn’t pay more than 200 RMB for a cotton shirt of normal quality.