You need...
A fermentation vessel...bucket.
A long stirring spoon..if you have a long spoon you don't need one.
A Syphon tube or if your bucket has a tap a bottling wand. A basic Syphon is probably cheaper.
Bottles. You can get free bottles from anywhere they throw bottles out. Plastic fizzy pop or water bottles are fine but they MUST have held fizzy stuff!
Sanitiser...you MUST sanitise EVERYTHING that comes into contact with your beer and kit.
Cleaner... You need to CLEAN everything before you sanitise. You can't sanitise muck! Get Wilko or supermarket basic,unperfumed,"oxi".
A jug...handy for topping up your bucket with water.
Hydrometer...cheap from Wilko...to test your starting gravity and your final gravity so you know fermentation has finished and it's safe to bottle..and your abv..
Sugar...silver spoon, cheap as you can find...you can do your beer kit with a kg of sugar. It'll be a bit thin but it'll be beer and it'll be drinkable. More money and a better result you can use a "beer enhancer" product. You also use the sugar to prime your bottles to give the fizz.
Nice to have.....
Airlock...to see the bubbles but not essential but they cost pence so get one!
So...you can do this for a small outlay ..
Kits...
The Cooper's are good start..as are Wilko.
Reality check...you won't be making Stella...it'll be a generic lager.
Patience....beer instructions are a bit enthusiastic...a decent brew takes at least 6 weeks...2 each of fermentation,carbonation and conditioning.