My GCSE Science is a website that has a video for each part of the specification of the AQA GCSE science course. It also has a series of GCSE questions with answers and multiple choice questions. It is a very useful website to practise each aspect of the course, but there is a probably overlooked gem which is free on this website and that is the blog.
The blog offers great insight into the exams and also how to do them. These posts include listing all of the maths questions in GCSE biology - because each biology exam has to dedicate 10% of its marks to maths questions - or providing a summaries of the examiners' report.
My GCSE Science has three levels of pricing. Entry level gives you quite a lot of videos and is free. Double award costs £24.95 and triple award costs £49.90. I would recommend that you try the entry level videos and definitely look at the blog.