You are very likely to have to pay anywhere - the government only supports students doing A levels up to the age of 19, so I doubt any colleges will be offering free courses to older students since they will receive no government funding for it.
Although having regular lessons, teacher guidance and homework is generally the best method for learning A levels, it is possible to self teach them if you are committed and disciplined enough - this also has the added benefit of allowing you to fit your studies around your work/ social schedule rather than having to stick to a prescribed timetable (although making a timetable and allocating certain days/ evenings to studying is a very good idea to keep on top of the work).
I would recommend trying to self teach some A levels, and perhaps looking into getting a private tutor just to top up your studies/ give you some extra support closer to exams. It is generally best to be tutored throughout the year, but perhaps having an hour or two a week and just increasing this if necessary nearer exams/ revision time would work well. This is fairly expensive, but you may be able to create a small class with any friends wanting to do a similar thing and it could work out significantly cheaper than a college course if you are prepared to put the work in yourself.
Of course, some subjects are more suited to self-teaching than others - essay based subjects are likely to be harder, and you are unlikely to be able to do a course with a significant coursework element. However, subjects like Maths are very easy to self teach from textbooks. What subjects are you considering?
Also, think about your motivation for studying A levels - are you thinking about doing further study at university afterwards or do you just want the A levels for your CV? Are you just interested in learning more about a particularly interesting topic? Don't feel pressured into having them just as an extra qualification on your CV because all your friends/ colleagues do - to a certain extent things like employment history can be more important than qualifications.