This guy runs high-end detailing business, and has made some great videos outlining how to wash and detail cars. He also specifies exactly what he uses with links to Amazon (and very few are fancy, expensive items) and shows basic techniques with inexpensive products and goes through some professional techniques and products. Any time I'm looking for advice on how to clean something, I look up his videos:
Basic Wash:
Basic Car Wash | AMMO NYC
Interior:
Interior Detailing | AMMO NYC
They sell cleaning products too, and obviously he will be using those, but if you look for products that are similar you should be able to get similar results. He often describes some products not to use and explains why they shouldn't be used.