Probably because IELTS, TOEFL and GRE are all organized by foreign institutions, and the registration fee for the exam is higher than that in China. But if you really want to go abroad for further study, bite the bullet. After all, this is very important for studying abroad. You should regard it as an investment in yourself. You have spent 1000 yuan on it now. You will have a better employment platform when you come back after studying abroad, so don't worry too much.
And if you decide to apply, make full preparations and try to pass as soon as possible, so that your money will not be wasted and you will not feel guilty.