I do Physics, Maths and Economics. I'm on AQA for economics and it's a nice break from calculations and stuff in physics and maths, just taking notes for an hour. That sounds boring but it is quite interesting.
It's a lot easier to revise than maths and physics because (on AQA at least) the exams are formulaic and you learn how to answer them to gain max. marks, For example AS 12 mark question, 4 marks for fully labelled diagram, 2 marks for relevant definitions, 4 marks explain the shift/relevance of the diagram, 4 marks for another explained relevant point, done 14/12 marks.
I find economics an interesting addition to my subjects as it is a proper real-life subject and you can really relate the supply/demand stuff to everything you see around you and every time I see an article about the economic situation, I read it and actually understand it which I find amazing.