If you want to be tinkering, playing with settings, upgrading parts, etc then get a cheap £200, but I wouldn’t recommend one.
Even a £400 you will be playing about with settings, but the quality & speed of the prints will be better and the settings shouldn’t change too much, and may not need setting up everytime you print something.
With all 3D printers, I say all but maybe not the £100k+ bracket, you need to know about 3D printing, we are a long way off being able to just press print like a paper printer.
I have a Wanhao D5S and its great, perfect for prototypes, making GoPro brackets, models, etc and the settings don’t drift and prints are consistent. I hear good things about the Wanhao i3+ and D4S. You need to narrow down what you want from a printer, then look at what printers would fit your needs.
You really do get what you pay for, but knowledge will take you from having an average printer to “oh my God I can’t believe you printed that on an i3!”.