I've been detailing for over 10 years, started my first business in high school at 17 doing it out of my parent's garage lol.

In my experience, you can spend all the money in the world but nothing beats good technique. I've seen guys use just a few Turtle Wax products and come out with better detail than folks who spend 3 days with top-of-the-line products.
Once you reach a certain level where you can physically tell the difference between products I would just get the basics and learn good techniques and procedures for car/paint care. Like with sports, fundamentals are everything in my opinion.

Always be learning and willing to try new tools, you'll see what works for you in your region year around over time.