I was in your position -- I tutored for a while to get the hang of the syllabuses in the subjects I wanted to teach (you don't need any specific qualifications to tutor other than subject knowledge and patience). Then I asked everyone I knew who was a teacher, current or retired, which schools they might be able to get me into for a day or two to observe (it is surprisingly hard to get schools to agree to this without a personal contact).
I applied for a PGCE but was horrified when I worked out how much it would cost me once I took into account loss of earnings. Then I realised that you don't have to be qualified for schools to employ you (although with a core subject like English that would mainly apply to academies and the independent sector). I got an unqualified post and was able to convince the school to train me we used the GTP, which has now morphed into Schools Direct. I now have QTS it took two years almost exactly, from the point where I decided to change career.
The point is I got paid for everything I did, apart from the days observing in schools, and I had a good idea whether I'd enjoy it or not by the time I started on the training.
However, there is a shortage of teachers in my subject (think about second subjects you could offer Drama? RS? Sociology is sometimes offered as an A level. You can do 'subject enhancement courses' to beef up your knowledge of second subjects the OU offer them and there are also specialist providers).
Good luck and be prepared to do loads of research and ask lots of questions, as changing career into teaching is really complicated -- not complicated to DO, if you see what I mean, but complicated to find out the info and make your way through the baffling language and assumptions! If you come across phrases you just don't understand, PM me...I was considering making a glossary at one point.
Good luck.