With a printer at hand and one of the templates that can be downloaded from this article, making a ruler out of paper is very easy.
Multicolored ruler templates
By printing this sheet of A4 format, you will get 5 rulers of 27 cm in four different colors.
Rulers with famous cartoon characters background
If you want to make a unique ruler with your own hands, you can print the following PDF, which contains 5 rulers with Pony, Car from Cars, Hulk, Superman and Mickey Mouse.