I think the following at around £3.50 each are well worth the money.
| ||GCSE Success Edexcel Maths Higher Revision Guide |
This book puts all the notes you need in one place with limited examples. All of the Specification is set out.
|GCSE Success Edexcel Maths Higher Workbook (GCSE Success Revision Guides and Workbooks) |
This gives lots of examples with answers to reinforce your ideas.
There are lots of sites that give you help (videos, worked examples, etc). This one is the BBC Bitesize – Statistics Site