Today most homes have a printer on hand and that makes it fast and easy to use online printable coloring pages. They don't take much ink either so you can find the value is there all the way around. If you don't have a printer at home you can often use those at the local library to print the coloring pages for a very small fee.
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.