According to public industry ranges: a single directive (LVD or EMC) is about RMB 3,000–9,000; an LVD+EMC+RoHS combination is about RMB 8,000–15,000; a full RED package for wireless products is about RMB 12,000–35,000; mechanical and pressure equipment, because NB involvement is required, is about RMB 15,000–80,000. Cost differences mainly come from product complexity, the number of test items, whether NB is required, and whether rectification and retesting are needed.
It is normal for quotes for the same product to differ by three times. To judge whether a quote is reasonable, look at three things: whether the list of test items is complete, whether technical file preparation is included, and whether rectification and retesting are included. Low-price quotes that only cover the "testing fee" are often made up later through technical files and retesting.