Caliart 240 Gel Pens Set for Adult Coloring Books Doodling Drawing Scrapbooking – 120 Coloring Pens Plus 120 Unique Refills is on sale for $14.99.
Previous price was 25.99 according to camelcamelcamel (got a notification).
Shipping is free with Prime.
https://www.amazon.com/dp/B07259LQPM