Here is yesterday's puppy, all grown up. In real life this doggy is called Ace. I made most of his lovely fawn colour using a little cad yellow light, some burnt sienna and white. But I also experimented with my new tube of Naples Yellow, a colour I have had a lot of trouble with in the Winsor & Newton range (it always looked grubby - I assumed it was me).
My new tube is a cheap Daler Rowner Georgian, not a professional oil paint at all. It cost £3.65. And it is FAB, a really lovely colour. By comparison, to buy this colour in the professional range by Michael Harding would cost RRP £44.09!! Good grief, as Charlie Brown would say.
Some teachers and art instruction books/sites are very fierce about only using professional grade paint. In my limited experience, whilst it is often very much better, sometimes it just ISN'T so the answer is to experiment and if you can't afford the Damien Hirst level prices of some professional ranges don't worry. After all, Degas painted on brown paper bags and Van Gogh painted on cardboard boxes, sometimes both sides of the same piece.
Whatever course you decide upon, there is always someone to tell you that you are wrong (Ralph Waldo Emerson).