The best way to learn and pass the exam is to join your local amateur radio club - there are lots around the country. You'll get loads of good advice and be able to try out different radios before parting with your cash. There are books available to teach yourself the theory and a few good online training resources as well - it's pretty easy and you shouldn't have any problems passing. The biggest problem you'll face is that there are a few simple practical exercises that you need to complete before you can take the exam, they are really simple but they have to be signed off by an approved assessor, so again this is an advantage of joining a club even if you only stay long enough to get your first licence.
RSGB books that will help you are "Foundation Now" and "Exam Secrets".
Good online resources are Bredhurst Receiving and Transmitting Society (Brats) and Chelmsford Amateur Radio Club (find them on Google).
I think the most versatile and best Boafeng model is the UV-5R, good range, dual band, easy to program, plenty of add-ons if you want them
Good luck
