Need to achieve black and red. Should I try to make it or buy my own? Is any particular recipe best for dying bright colors?

Buy it.

Buy it, I tried to colour fondant black once and would never do it again

I always buy red and black. It's very difficult, at best, to achieve true colors when it comes to red and black. In my attempts, it always came out sticky and unusable.

Buy the red but make the black. I oddly don't have issues with black, in small amounts that is. LOL. I use Duff's black or Americolor black and it works wonders. But, if you're not sure buy both. Good luck!