Research the position and tease apart the salary they offer while comparing it to your current earnings, benefits package and rewards, including pension, holidays, and healthcare. You can also volunteer any offerings your current employer offered to keep you on and what your calculated annual earnings would be after one or two performance review periods. Then share this with transparency without offering them a conclusive number. Simply share where you are in your career and how your goal is to find the ideal employer who feels like the right fit concerning culture, working environment and developmental opportunities. Explain you are hoping they'll recognize your professional worth and would be willing to incentivize you to move over to their teams. This keeps the conversation going and doesn't close the door on negotiations.