I've used both Alumilite and Castin' Craft dyes. Alumilite dyes cost less but not all of them are compatible with polyester resin so beware if you use Silmar 41 or Castin' Craft resins. I doubt you'll find a cheaper price for Alumilite dyes than on their website. The price of Castin' Craft dyes can vary quite a bit, so shop around if you go with those. That being said, I prefer the shimmer of mica powders to the solid look of dyes, and using both dyes and mica can give some nice effects where you only have the shimmering effect in certains areas/colors throughout the blank.
