Patent costs come in two buckets: professional fees (drafting, prosecution) and USPTO fees. A provisional application typically runs $2,200–$4,400 in professional fees. A well-drafted nonprovisional utility application typically runs $6,600–$8,800, plus $800–$1,600 in USPTO filing fees for a small or micro entity. Office action responses add $1,500–$3,500 per round. Design patents are considerably less expensive — typically $1,500–$3,000 in professional fees with lower USPTO fees.
International filing via PCT adds another layer of cost. The honest answer is that a utility patent from filing to grant, including prosecution, typically costs $10,000–$15,000 — sometimes more for complex technologies or contentious prosecution. Fees are discussed transparently during the discovery call and a clear estimate is provided before any work begins.