Hi Glo! It depends really on the project! Is it more competitive or less! How many keys…sites…! In case of OFF-PAGE-OPTIMIZATIONS you have to calculate always the costs for the Backlinks (quality & high authoritive sites). For some cases (example: longtail keys, local businesses) there is just enough sometimes to have a great onpage optimiziation & citation links (yellow…)! I use THE SEO TOOL AHREFS to check the competition and how difficult is a ranking! For Onpage-Optimization you calculate how many hours you need for…and as I said this is always different for each project! Always individual prices! I do online coaching in that case I have a fix price! But the rest is for sure individual! And if you get a off-page contract from the customer - you can keep him “forever” ;-)! If you give him great results! Never tell “im gonna rank you on 1” ;-). Best regards.
Best Regards Marko J.