There are several types. The 2 yuan price in the answer above is probably not from Shanwei locals. It’s nonsense. It would be nice if it was that cheap.
One is breakfast noodle soup, usually shrimp, meatballs, etc., usually 6-8 yuan
The other is lunch noodle soup, usually beef brisket noodle soup, usually 6-8 yuan 10 yuan
One is late-night snack noodle soup, which is usually 10 yuan. There are no late-night snacks priced lower than this.