PC Speakers?

Search Internet for some nice brands.  You can read reviews about the better ones.  The high priced ones from B&O, Harmon Kardon, Yamaha might be too much.

Try Ebay because some people get rid of them when they get home theater units.

Amazon or ebuyer would be your best options depending on where you are.

How good are you with woodworking tools? At your (or my) price range, you won't get any of the fancy DSP-corrected active monitor speakers (change my mind ;-) ), so the next best thing would be to build a pair of decent passive speakers and pair them with a small class D amp.

My favourites (i.e. what I'm using right now) are called "Maxi-Beep" and are about as serious as they sound. Also known as CT279 from the magazine "Klang&Ton" in 2015. A full kit (without wood) is sold from e.g. https://www.lautsprechershop.de/hifi/ct279_en.htm or http://www.spectrumaudio.de/index.html, but you can get the bare drivers e.g. from RS components or Parts Express for around 15 €/pounds/dollars each.

Full documentation from the developer is available here (in German, so the measurments are in mm, not inches :p): https://www.diy-hifi-forum.eu/forum/showthread.php...

Add an SMSL SA-50 (Amazon, ebay)or something similar as amplifier.

Try the Logitech Z506 5.1 surround sound speakers.

https://www.logitech.com/en-us/product/surround-so...

https://www.amazon.co.uk/dp/B001IZZ2PE

orhttps://www.amazon.co.uk/GigaWorks-Multimedia-Audi...

Creative Labs GigaWorks T20 Series ot T40 series      £69.98 or £79.98

https://www.amazon.co.uk/Genius-SW-G2-1-3000-70W-S...

Many years ago (15 or so) I bought a set of Polk Audio speakers with sub at a discount store for $15 or $20, somewhere in there.  I'm still using them right now and they work just fine.  Around that same time I also bought a set of Logitech speakers

, also with a sub, for somewhere in the range of $30.  Those things work great and sound great.  As I've had no reason to buy PC speakers since then I don't know what the prices are now, but surely you can find something that sounds very good for less than $50 (or the UK pound equivalent).

Any speakers with a small amplifier will suffice but I'd advise getting those with a sub minature ( barrel shaped) connector rather than dedicated computer speakers that are USB connected. Just my preference based on long term reliability.