Why do you need a tutor yet you can use the internet all for free?
I would advise you to buy revision guides for the science subjects or even use youtube and watch science videos such as westlands science that explains the topics really well Unless you're really really struggling with science then I would recommend getting a tutor
Have you checked out the internet resources available yet? There are incredible ones on YouTube for all of the sciences - they're amazing at describing the tough concepts with such ease. It could possibly alleviate the requirement of a tutor.