I sat at the feet of a Golden Daemon winner about 10 years ago. I took his advice and rolled with it and my painting has plateaued but I am happy with my results.
Windsor and Newton brushes are expensive. but. If you take good care of the brushes, they will last a long, long time. There are acrylic paint cleaning solutions. get a bottle of that. Run your brush under lukewarm water. If the water is too hot it will make the wax (that holds the bristles together) melt, causing the bristles to fray. Dip the whole of the brush bristles in the cleaning solution then run thoroughly with the lukewarm water coming from the faucet. That said, the one brush or type of brush that I don't spend a lot of money on is dry brushes. They get thrashed anyway, just make sure they have a nice stiff bristle, like GW's.
As for paints, I use Vallejo paints for everything but metallics. Vallejo paints are cheaper, just as good if not better than GW, and it comes in eyedropper bottles so getting exact ratios is much easier. GW's metallics still have the highest flake concentrations. For inks, I use either Vallejo or Windsor & Newton. Hope this helps.