I use one one I got at a "real" auto parts store, not a retail outlet for spoilers for Hondas. I think it is made by Lisle.
Get some spare or scrap brake line, and practice making flares, before you work on a critical line. You can also buy several premade brake lines, that are too long, and cut one end to length. Use the short ends for practice.
Buy extra flare nuts, and maybe an extra coupler or two.