I can’t answer questions about value, except to say that natural stones sell for more than synthetic.
Remember, though, that synthetic, or “lab created” stones are just as real as natural stones. They are the same material, and usually pretty much flawless. For quartz, in particular, it’s not easy or cheap to tell the difference, and a large percentage of the quartz sold as “natural” is actually synthetic.
Simulants are another class. These are stones which look like natural gems, but are not the same material. For example, CZ and moissanite are often used to simulate diamond.
What you cut will depend on what you can afford, and your reason for cutting. Cutting for sale is not the same as cutting for your own enjoyment.