I've tested a lot of different power cables over the years. And something that often surprises me is the fact that, when I change signal cables, for example, the sound "changes", while when changing power cables it is often very obviously "worse" or "better".
With a limited budget, I can really recommend Wireworld's cables. From the cheapest entry model and up. I have always thought that they provide a positive and steady improvement overall. Their copper cables are preferred, while the silver models require caution and testing ..