[DNukem170]

First off, do NOT use oil-based paint markers. They all suck. Only get acrylic.

I've had great success with Sharpie Creative Markers. Goes on smooth, dries quickly. You can get the multipack from Walmart for $20. Do be aware that doing multiple layers using blue and purple long after the first layers have dried will often made the shades much lighter, for some reason.

For a better color selection, I have also been using Artgn, which has the 60-pack for $26 right now on Amazon. The finish isn't as good as Sharpie's, but still smooth.

There are only two real issues I've been having with them. One is that Red is significantly lighter, no matter how many layers, than the caps indicate. I haven't found a paint pen that gives a rich, deep red.

Second issue is that painting joints can be annoying, since they'll obviously flick off if you try to move the limbs. After all, the paint isn't going into the plastic, it's forming a shell on top of it.

Also, make sure you get brush tipped ones. They're far more precise and easier to use.