A postgraduate certificate only means that you have been trained in postgraduate education courses. It does not issue master's certificates.

You'd better ask whether the unit needs a diploma (master's degree) and a certificate of completion (graduate equivalent) when asking for professional title evaluation.

As for money, many universities in Beijing (including Tsinghua and Peking University) now offer such courses. After paying the tuition, I will give you such proof for one or two years. You can attend classes on Saturday and Sunday if you like, and nobody cares if you don't listen. You don't care what you study after paying the money. So 5000 yuan is possible.

The key is whether you can use this card after you get it. Don't be fooled by China's Chinese character skills.