I'm looking for a gaming/word professor desktop that is affordable?

I'm 14 and hardly know anything about desktops
I'm looking something that can handle games such as minecraft etc

I don't really mind if it is slow on word, I can handle that
The price range is 0-300

If you could show me a good desktop that is good for that or a site that has desktops that would be great

Well, here they provide "packages" where you can buy a chasis and its parts from anywhere between 200 - 500 on the lower end. For a decent one, though it takes about $400 or so.
Wherever you are (I assume UK) go look about and see if its cheaper to buy a second hand computer or its parts (Motherboard, Harddrive, DiskDrive, Processor, Fans, Chasis, Power adapter, graphics card(? To get a cheaper deal. If you want to play games like minecraft (if you aren't the one hosting the server) then a i5 processor, 8GB of RAM and a 250GB harddrive is more than enough to play smoothly (altough it may be out of your price range)
I'm from SG by the way and i'm not sure if you can get one from here but if you do you'd benefit from the conversion rate because pounds to SGD is about 2:1.
The link for the store I got it from will be in the sources

may not be completely helpful but at least you know some specs.
(an i3 processor may make it)

For your budget you will need something like this system: https://www.amazon.co.uk/...B00DWTJW6O
AMD A6-5400K processor
500GB SATA hard drive
4GB DDR3 RAM memory

You will want the AMD A6 processor for its integrated GPU, which will be the one of the few integrated GPU's that can play games at a decent rate. The A6 also has quad-cores, so it'll be very good at multitasking. The only downside is that you'll have to buy a Windows OS separately for it, which might add £55 to it. But if you already have Windows from before, then you can save on this purchase price.