Short answer: English editing pricing is usually based on manuscript length, the amount of language correction required, academic complexity, and turnaround time. Light proofreading and substantial language editing should not be priced as though they are the same service.
Ask whether the service includes grammar, academic tone, terminology consistency, readability, tracked changes, and comments where meaning is unclear. If a target journal has specific language or formatting instructions, provide them before the quote.
A short sample review can help determine whether the paper needs proofreading, standard English editing, or more extensive scientific editing. This avoids buying a service level that is too light or unnecessarily expensive.
Journal acceptance is never included in an editing fee because editorial and peer-review decisions remain with the journal.