The Drippy Smiling face can only be purchased with $DHC which you can buy at Alcor or Taco if you're not earning it in the Farms or by working in the Horde's Discord.

Also check out the CRAFTS.
You need to burn 1 black and white Drippy Smiling Face with any 2 assets from byronartset1 and 200 $DHC to get a coloured version.
Click the Colour you want to go to that crafting page.

If you have all 5 colourful Drippy Smiling Faces, you can craft them into the limited edition Colourful Glowing Drippy Smiling Face. 

To do so, go here: