Most of my readers have more formal education than I do. My only achievement on leaving school at 16 was proving that I was not ESN (having an IQ below 80). In fact my IQ was 133 and the reason I could not concentrate was that I was bored. I think this is the case with many disengaged boys in school today. Very little is expected of them and they would do better if it were.
One answer is to educate yourself. It is quite possible to do this while working and without generating a huge pile of debt.
The first resource I found was Alison. This is a great bunch of computer based learning packages (over 100) that you may pick from as you wish. They do not result in a recognised qualification because they are done at home rather than under exam conditions. Nevertheless you are tested at the end of each course and your results are posted on a public web page you may direct employers to.
One interesting thing about all self learning is that most people do not have the discipline to do it. I have just completed unit two of psychology on Alison and found that only 67 people have completed the course even though 409 have started it.
Another, similar resource is the Email College. This site is run entirely by volunteers is a magnificent example of the generosity of internet folk. Unfortunately it is less professional than Alison and contains courses on pseudo subjects such as numerology as well as more useful things. You may also like to look at About U which is a more commercial but still free alternative.
Finally we have Open Learning which is a product of the Open University. The Open University is an internet based state university based within the UK that posts its lectures and its reading materials on the Internet. This makes it possible to gain a degree very cheaply even if one works full time. The Open University has made these materials freely available to anyone who wishes to study them. Open Learning will not result in a degree as there will be no summer school or examination at the end but it is possible to point an employer to your record of study. You will also find that you can download Open University broadcasts through the iTunes software.
If you prefer to learn face to face you may prefer the School of Everything. This operates rather like an internet dating agency but puts teachers in touch with students. You are then free to contact them directly.
The BBC also operates some free online courses. Their offering is rather fragmentary because they have a number of conflicting purposes. Skillswise, Key skills 4 U and its private sector alternatives are very good adult literacy and numeracy resources but they do not not result in a qualification although Move On can sometimes do so. It is possible to use the move on site in combination with a free course that is held in most local colleges. If you take the test (and pass) you will then be issued with a certificate. The Languages section of the BBC site is better than many paid for products and the most impressive thing I have found on the Internet so far. This site even includes a sort of interactive soap opera where characters talk to you and threaten to hit you with saucepans unless you make yourself clear. Great fun. There is also an extensive site dedicated to helping children with their GCSE's, some of which may be useful to adults. The remainder appear to be a mixture of TV tie ins and green propaganda.
I would like to finish by mentioning two more government resources. First there is Advice Resources which is intended for people working in the many government advice outfits that grew up during the Blair era. In reality you are far better going directly to this site that you are trying to get help through the bureaucracy. There is also the Teach ICT site which is aimed at computing teachers.
Finally we have the completely useless Skills Account which employs a vast number of advisors who do nothing but call one another lies! If you try to open an account they will mess it up and if you try to close it they will refuse to do so and then phone you up at home. Avoid.
The great beauty of this approach is that it may be tailored to your own life goals. Here is my own plan to give you some idea how this might be done. Your own plan will be completely different but it should reflect what you are trying to do in life.
You may also follow a less structured approach by selecting whatever you need from wikiversity or work through the various free resources put out through the British Libary.
Some resources are not designed to make sense on their own- such as this GCSE Maths revision site and this more general site.