Providing an easy-to-understand pricing structure with clearly defined services will give you a starting point and something easy-to-pitch. Also, a clearly defined service list prevents endless negotiating battles from listing to listing.
Does that $200k property want advertising on your website? Up-sell! “For an additional $300 fee we’ll advertised your property on our website.” A pricing structure is written in Word, not stone. When needed, make exceptions and keep your business flexible with the market.