Adult coloring books are still pretty popular, I see many varieties still being sold at book stores near me. If you've been a fan since they first got big, or you're still waiting to give it a try, jump on this deal for a set of 80 gel pens that are now 75% off regular price with free shipping for Prime members or on orders over $35. These non-toxic pens come in a variety of glitter, metallic, neon, and standard colors with an easy to transport clear case.