Learning Mathematics with technology is not only necessary but it is fun. Your calculator is an important tool that you will need. Be aware that for the exam you need a basic scientific calculator as data storing devices are simply NOT ALLOWED.
That said once you get a calculator you should know it as if it were an extension of yourself, know its strengths and weaknesses.
Here are some good ones
Texas Instruments TI-30X II
If you are an enthusiast like myself and want to go really Hi Tech then the
Texas Instruments Nspire CX CAS Graphing is perfect. But you wont be able to take it into the exam.
Smart Phones & Tablets
Your Smart Phone can do a lot more than social Media. Download a scientific calculator or a graphing app and you have at your fingertips an incredible tool that will bring your graphs to life. Here are a few;
Graphing Calculator by Matlab
Desmos Graphing Calculator
These are available from the Google Play Store
Math Training App
Math Tricks by Antoni is perhaps the most fun app to learn Arithmetic and Numeracy skills. It has several training options, single player game mode as well as a two player game mode.
This app will help you develop your number skills for paper 1 which does not allow calculators. It is available from the Google Play Store. Its highly recommended.