This year I went in a Homemade Mystique Costume. I started off by purchasing a blue unitard from an online discount dance supply store. After making sure it fits nicely - after all I was going for a bare skin look - I proceeded to paint it. I used watercolor (the kind that comes in a tube) for this, so that I could wash it off, if anything went wrong.
Using my fingertips I created darker spots, which I later traced in white using a fine brush to create a 3D effect. I painted the unitard while wearing it, so that I could tell what it will look like when it is done. When I was through with the front part I put the unitard on backwards and painted the back.
I used spiking glue and lots of hairspray to slick my hair back and then dyed it fluorescent orange using a wash-out hairspray. Facial make-up was done with 3 types of facial paint - blue (general skin tone), black (to create a pattern) and white (to highlight the "ridges"). It just so happened that I already owned a pair of blue shoes in a croc pattern, so it worked perfectly with the overall scaly look. I painted my hands and feet last, using the same technique as my facial make-up to make everything blend.
Time spent: about 5 hours. Money spent: just under $50. Was it worth it? Absolutely! The costume was a hit, wherever I went.