What camera is best to get, for a beginner photographer?

Ok, so I enjoy photography and I would like a more serious camera, but also something that would be suitable for a beginner.
Also I would like it to be reasonably priced as I'm a teen and paying for it myself.

The best beginner camera is any dSLR or even a used 35 mm SLR.

Your first goal is to learn the fundamentals of photography and how to use the camera.

This can take over six months

If you buy a used 35 mm SLR (under $100), you will become more disciplined when taking your shots since 1) you are limited to 36 exposures per roll and 2) you have to pay to have the film developed and printed (pay as you go).

After you are consistently producing amazing shots, each time you press the shutter release, then consider buying a used dSLR that uses the same lenses on the 35 mm camera.

If you want to be able to use the same lenses on a Canon dSLR, only consider a Canon EOS 35 mm camera. If you buy a Pentax 35 mm camera that uses K-mount lenses, you can use the same lenses on a Pentax dSLR. If you buy an auto-focus Nikon 35 mm camera, you can use the Nikkor lenses on Nikon dSLR cameras and finally, if you buy an auto-focus Minolta 35 mm camera, you can use the lenses with any of the Sony dSLR cameras.

As you can see, you still need to do a lot of independent research.

You will get lots of good advice on here, but I would add something.

Work out your budget. Allocate 75 per cent of it to the camera/lens and the other 25 percent to materials devoted to learning about the various skills involved in photography. This could be a book, an online course, a DVD, or even a lesson from a photography teacher (be careful with that last one though, threw are a lot of incompetent idiots out there who think they are qualified to teach when they are in fact not even qualified to clean the camera of a professional).

If you spend the whole budget on the gear but don't learn how to use it to its fullest, then you'll be relying on trial and error to improve. This is possible, but takes longer. A little study and practice and you will start seeing a) how much self there actually is to photography, and b) how many different approaches there are to it.

Anyway, enjoy the process whatever direction you take.

Canon 1100D or Nikon D3100 (both under £300)

Canon 1100D or Nikon D3100 very very cheap!

Any Canon Rebel is great for beginners who are actually serious about photography. I got mine when I was 13 (started saving up from allowances and christmas, birthday money for a year though) and I wouldn't regret buying it ever because you will use it for a long long time and they are VERY nice cameras. For me I got the rebel t2i but they have different variations of a canon rebel. That was my camera and now I'm enrolled in college to pursue in photography and I still use it!

Nikon D3100 or Canon Rebel T3.