All you have to do is laminate construction paper and then have one of your new & excited kindergarten parents that are always so willing to help, die cut the letters of each color word from the corresponding colored paper and then put them in a ziplock bag.
Here are the letters stuffed in a bag...
The kids then dump them out on a table or on the floor and sort the letters by color.
...and then they spell each color word using the correct colored letters. For example: use the red letters to spell red, blue letters to spell blue, yellow letters to spell yellow, etc.
As an extension, my little ones love to then write the color words using the correct color of crayon. For example: use red crayon or marker to write the word red, blue marker/crayon to write blue, etc.
Now wasn't that cheap AND easy?!