I'm not going to mix together a million shades of the color purple to match a comic book character who actually changes slightly between issues, especially when it doesn't matter because the camera will make it look lavender anyway. I bought a tube of paint that said "purple" end of story.
craftsmart is the cheap brand. I use Anita's for most of my work, it's still only $1 per tube but applies nice and smooth, however it can chip and peel on plastic so I have to use a sealant spray to protect it. I also tried Testors acrylic, it also applies smooth and doesn't need a sealant. Both of those paints don't dry very well on polymer clay though, and stay sticky. I've been told that citadel acrylic is much better on polymer clay.