The kit you showed works. But it is very tricky to get consistent, usable results. Lots of practice is required, as is close examination of the produced flare. You must cut the end square, and deburr bother edges. I use a small wheel type cutter that you twist around the pipe, as it's quicker and easier than using a hacksaw, plus it guarantees that the cut is square. I've seen them in both Machine Mart and B&Q for a few quid.
If you're feeling flush, check out Automec's website, their flaring tool is almost as good as the expensive Sykes ones that garages use. It's about a third of the price. You definitely want the small bending tool; it looks hopeless, but effortlessly puts tight bends right up to the end of a pipe. It's much better than bending the pipe around a broom handle.
Buy both the pipe and fittings from a motor factor; a coil of Kunifer is about a tenner, and the fittings are a few pence each. Get several of both male and female. You'll need metric ones.
When making pipes, get in the habit of sliding the fitting onto the pipe just before forming the flare. But you will still forget sometimes, everybody does!