This is the final part in the list; hurrah! The PSU is another component that some people cut corners with. But, be warned; cheap PSU's blow up! Not like cars in a Hollywood blockbuster, but they can certainly fry your system.
At the time of writing, getting hold of a decent PSU is hard work, due to shortages brought on by COVID-19. This has made it hard to find anything I would recommend.
I have settled on the Corsair CV450, which is excellently priced at £40. The 450W power supply is plenty for the above mentioned components and has an 80+ bronze efficiency rating.
There are a couple of drawbacks. Firstly, it is a non-modular unit, meaning there will be way more cables than you will need, which might make cable management a little bit harder than a semi/fully-modular unit. Secondly, the cables themselves are the ugly "ketchup and mustard" kind. These can really detract from the final look. If you want to avoid this, you could consider buying some sleeved cable extensions, in white (see below), to match the overall theme.