Ei papers refer to papers published in EI journals, that is, there are both English and Chinese papers. As of September 27, 2022, the page fee for a paper published by this journal is 500 euros, equivalent to about 3452 yuan, far less than 6000 yuan, so it is expensive. Some journals with sufficient strength, sound publishing institutions and firm academic beliefs will choose this charging model and even reward authors. If there are fewer free general periodicals, there will be more free cores or periodicals. However, the number of articles published in this journal is very small and it is difficult to summarize. If you think your paper is quite standard, you can give it a try.