The short answer
Wire distribution alone runs from free to thousands of dollars per release. According to PRLab, "prices range from free to $5,000 per release," with pricing "typically" from "around $50 per release for basic online distribution to $800+ for national newswire coverage," rising for global reach, extra word count or multimedia.
Writing and media servicing are separate from those wire fees. This site does not publish Susan von Seggern's fees; her campaigns are individualized. If a client budgets for a wire, her annual Business Wire arrangement significantly reduces cost compared with buying a one off release from Business Wire or another wire.