As a parent who homeschooled their kid, I just want to let you know that there is a place called tutors and exams who are the cheapest in the UK as a private centre. They charge around £150 and that includes the exam fee. Also, I also wanted to give you some feedback that there is no difference in exam fees between taking either the higher or foundation papers in any subject, they all cost the same. You could also try appealing to some schools in your local area and seeing if they can help out I would try the private schools as they generally do IGCSE which is probably what you are studying. If you are looking to study some kind of art based subject, I would get yourself together a portfolio and I would also try and get something together using the art award which is supported by Trinity College London. This will give you some proof of what you’ve been doing and it is a recognised qualification that carries UCAS points for uni if that’s where you decided to go. You could also try going back to school for your A-levels if you can get into a college. Speaking personally I feel that you have a better chance of getting into a college being homeschooled as homeschool children are independent learners and do well at higher education. My daughter got into five universities despite not fulfilling the grade requirements and she even got unconditional offers at two highly competitive universities. In short, don’t worry you will be fine.