Amazon has a seller that sells nickel-copper for $25 for 25 feet. Sure it's double the cost but won't rust and is far easier to work with. The cost difference is really insignificant considering the amount used plus your time. It's your call but for a first timer it's the way to go.
I am using this as the flare tool
KTI70081 | Vehicle Specialty | Vehicle Specialty Tools | Product Categories | Tools | K Tool International Site
Yes it is expensive (about 199 on amazon), I got mine for about $50 less new on Fleabay. I figure that I will have this tool for a lifetime so might as well buy a good one.
I had one of those cheaper handheld units and I keep it with my emergency tool kit in my 60.
it works very well.