I've had my macbook for about two months now and got it working roughly how i want it to. But I've just found that Garageband is taking up a stupid amount of space. Is there an uninstall option for this and all its associated files?
The short answer is no, not built in. If you want to you could use one of the shareware options like AppZapper. But you could do it yourself. Delete the app and anything in /Library/Application Support/GarageBand (that folder on my machine seems to contain all the loops and is 1.92Gb in size). If you want to be more thorough the do a Spotlight search for GarageBand.