Hi Jamestown,
Perhaps not really the question this forum was created for. As you ask about details for your business model and not at all about anything related to Cinema 4D directly. It has also a little bit of a hint of an advertisement - which is not really wanted here.
Let me put it that way, purely theoretical:
The price is certainly based on what you personally need to stay in business and how much you constantly can produce. How much the distributor takes as well from the income …
Your competition has certainly an idea about all of that, check them out. (Ask your self, can you build it for that money, would you can sustain your business against others?)
Place all numbers in a row, whatever you touch during the production needs to be paid, including 401K, health insurance, tax consultant, computer/software, etc, often people forgot many little things. Little as in copyright for your objects, textures etc, in both directions, getting and taking, for example.
All of that, and more, will give you a direction. Which is from my side not a professional advice nor any suggestion you should rely on, what ever I write here. As this is not a business forum.
To ask here without anyone knows how your constant quality will be, your support and your willingness to refund and advice to users, etc will determine your long time value = price.
Just start and test things out. :o) You have asked over the last three years many times here about similar things. I take that as a sign that most of it is really what drives you! So, I’m not certain what else to say other than to encourage you: Just put your models up and if they don’t sell, lower the price. Allow for some time! If they sell well, leave the price and add a little bit to the price-point with newer objects; Just a thought.
What people are willing to pay depends, from my point of view certainly, on several points: How desperately they need a specific model, how much variety is offered already, and last but not least the provided quality.
If you create an integral style among all models, people might see how much they are able to add other parts later on—this might stabilize your business, the idea of collecting. Allow them to imagine that over time they get a library that works together, instead of single un related pieces.
My best wishes for your next step.