PAINTs:
I really like painting the head kits I sell on ETSY with Reaper Miniature Paints. The results are much smoother than Hobby Store paints and you can paint better details.
Reaper Bones paints
This is my favorite primer for painting 3D printed parts:
Tamiya Fine Primer gray

LOW Cost ARMATURES:
I’ve done quite a few projects with these lower cost armatures($65). They hold up well, but if you are trying to do a feature long film…then I suggest going with something from the links in the next section.
11 inch Armature Low Cost

ARMATURES:
AnimationToolKit (UK)
JulianClarkArmatures (UK)
Kinetic Armatures (SPAIN)

RANDOM SUPPLIEs:
Green Screen Lighting Kit great low cost starter kit to start lighting your stage
Gaffer Tape you always need this stuff! I keep green, black, and white on hand.
Silicone Rubber for Casting for casting body parts. I 3D print the molds.
Van Akin Claytoon Clay I usually make beards, eyebrows, and eyelids from this.
Dragonframe Software industry standard for capturing stopmotion. Has a great tool for timing lipsync.
3D Printer with Wash and Cure station I find these printers to be really reliable and easy to use.
Mini Sewing Machine Kit this comes in handy for sewing puppet clothes.
Sticker Cutting Machine this is great for cutting out stuff that is too hard with scissors, like sticker mouths