You have a greater tool - your PC - that can be helpful to get the printouts of diverse colorful sheets. Guide the children, exclusively during the holidays to add illustrations to the colorful-page, and showcase them around the prominent places of the house. This will give them, a sense of pride and joy for their creativity, and would lead to further productive pursuits. Thus, you will witness that there are massive advantages of coloring-page relatively to coloring books. Coloring sheet are economical, costing you only a couple of cents in ink and paper rather than a few dollars for a coloring book.
You have two recourses to opt, either keep a stock of colorful-sheet, or give according to the need of the children by getting the prints of coloring-pages from the PC. In case, you may start to give coloring book, then after exhausting a coloring book, you may need to do hassles to get additional coloring books plus they may use up additional space. Every time you discover a particular favorite picture in a coloring book and desire additional copies, you have to either locate a photocopy machine or Purchase various duplications of the book for a single page. Any time you see a good image on a coloring sheet - you can bookmark the website and get the colorful page from it, according to your need.