As @Psygnosis has mentioned looks like they have now removed the 20% off option for all 3 colours.
Bought one from a recent deal to test it out. I must admit I was somewhat blown away. So bought a few more.
Make sure to select "Apply 20% coupon" first and then enter the promo code AQQO99XH during checkout. That should get the price down to $8.38.
Do note that it's a single-use code and for me at least I could only get it to work properly with 2 max (also must be 2 different colours) in the cart with all 3 it just spazzes out for some reason.
Also if you buy 2 it qualifies for free shipping without Prime even though the total after discounts is only $16.76.
I'm no psychic but I know what you might be thinking right now. He must be really famous to have so many fans?