I ran across this site last year and knew that next year my 16 month old twin girls would be at the perfect age/stage to be Thing One and Two. So I saved your site and this is what I came up with for Halloween 2008.
Their costumes were crocheted by hand and NO pattern was used. We live in Florida so the no sleeves worked perfect with the top tying around their neck. I wish I had a picture of them standing, the pants are flair legs and super cute.
My biggest worry was the how to do the hair. So I was on the hunt for the wild blue hair! I knew they were too young for me to spray paint their hair and I couldn’t find blue wigs small enough for them so I decided they should be made out of the yarn too. It worked out perfect they did not mind wearing them at all and they even keep them on the whole time!
The only cost involved was the yarn and some time!
Related costumes:
Coolest Homemade Wild Style Costume from the Lego Movie 
Everything is AWESOME about this Emmet Costume 
Coolest Kid’s Haunted Castle Costume 
DIY Super Hero Family Costumes 
LaLa Loopsy and Where the Wild Things Are Costumes 
Once Upon a Time Costume: Young Adult Snow White the Bandit 
Prize winning DIY Lego People Costumes 
Coolest Peacock Costume
Are you willing to sell the wigs? I need them for the twins first birthday next Sat?
I have a 2 year old and a 1 year old and am doing similar costumes…it never occurred to me to crochet their hats instead of struggling with a wig! I’m an avid stitcher… what kind of yarn did you use? Specific color?