In the real world there is no difference between gold and silver XLR contacts as for transmitting sound. Millions of XLR silver plated XLR connectors are used throughout the world. Or to put it differently, the best thing about gold in these applications is that it looks good with black.
Low priced snakes can work quite well, but the can also have all sorts of problems. Generally quality pays off in longevity and ability to stand abuse. Any time your most important mic input is disturbed by crackles from a bad solder joint in your low quality snake, you are going to hate yourself for beeing cheap. But going for quality is not necessarily the same as paying extra for things like gold plating.
Gunnar