Brake Flaring Tool....Best to Buy???

Another vote for Eastwood. Their flaring tool along with their brake line deburring tool has gotten me a perfect flare 100% of the time.

https://www.eastwood.com/eastwood-on-car-flaring-tool-for-3-16-tubing.html

https://www.eastwood.com/eastwood-tubing-deburring-tool.html