There's a few wide-open variables in a seemingly simple question: 1) people have pretty different perceptions about "expensive" 2) different types of music can have very different requirements (in other words, you can bang out beats with nothing but a laptop but recording an orchestra is not gonna happen without some decent gear) and 3) "decent" is also a very subjective thing.
That said, I'd say anyone with the skills and vision can make, well, decent music with just about anything these days - it's more about making the most of what you have rather than worrying about whether or not you need this or that to achieve something. There are of course some things you can't get around: we still need microphones to record stuff outside the computer, and good monitor (speakers) are rarely cheap. The high end stuff has its place, even if the sonic gains get relatively smaller the higher you go - and it's not always just about that this thing sounds 200% better than that thing, but also how it feels and how it makes you work.