Why is there a price difference in dental tooth crowns? explanations please?

Cost of crowns: The answer is the same with cars, houses, food and most things in life. Namely, cost of materials (and time necessary to fabricate)- that's at the same office. Crowns that have gold usually the most costly. Between offices include overhead costs such as geographic area, type of practice, lab costs, salaries, insurance, expertise of dentist.

Materials / labor: If you get a gold crown or a porcelain fused to gold or high noble metal, there is an additional charge for the precious metal, usually based on the price the day it was made. Labor and skill of technician required to fabricate crown can also be a factor in laboratory cost to Dentist. Also, some may require more time / skill to prepare the tooth. All ceramic often less than porcelain fused to gold

Fees for crown: can vary widely, even in the same geographic area. It might be different dental laboratories, it might be different materials (porcelain, ceramic, gold) and all dentists are not the same.