Here is a short re-cap of B's previous costumes:
2008 - Tigger (we were busy renovating our house and last minute costume selections were sparse for a 6 month old a.k.a. pooh, piglet or tigger). A bonus.. I think I only paid about $15 since it was on clearance.
2009 - Skeleton - we bought a pair of skeleton pjs for $8 and a skeleton hat from the dollar store. Needless to say he got much use out of this costume for under $10
2010 - Construction man - we already had a play construction hat and jean overalls. We got him a set of play tools for $2, borrowed a small tool belt off a neighbour which we doubled around him, and I smudged some charcoal eyeshadow on his cheeks for good measure.
This year, after changing his mind several times from robot to scarecrow to clown, he finally settled on being a gnome Halloween morning after watching one of the latest favourite movies, Gnomeo and Juliet (love the Elton John soundtrack to this movie!). Lucky enough, I stumbled across this tutorial online. I ran out to the store and grabbed some faux fur for the beard which was 50% off so cost me $3.50. For the hat, I cut up one of DH's old red work t-shirts, hand stitched it into a hat, and stuffed the top with some tissue paper I had lying around the house. I safety pinned the beard to the hat and he wore his yellow rain boots. Voila! Year 3 of not spending over $10 for a costume.
B was almost too sick to make it out but after seeing the first few kids come to our door, magically felt well enough to get dressed up and hit a few houses on our street. He got lots of compliments on his costume!