I used some outgrown school clothes to make his costume.
First I found one of his old school shirts from last year that was on the grubby side anyway...
I threw three black teabags into about 1.5-2 liters of boiling water.
I then rinsed the shirt in cold water and hung it out to dry.
When it dried, I ripped off parts of the sleeves, and tore into the pocket. (As it is still cold out I was concerned A would freeze with too many tears...)
The shirt turned out really well, much better than I had hoped for.
For the bottom part of the costume I used a pair of scruffy P.E trousers that were already riddled with holes for some reason.
I cut the cuffs off the legs in a zigzag fashion. And cut a few holes into it.
A added an old scarf as a belt onto which he strung the pouch he uses for Cubs and tucked in a wooden knife S lent him. Alternatively it's quite easy to make a weapon from sticks and rope.
What I really like about this costume is that I could recycle old clothes that we no longer have a use for, my only added cost was 3 teabags, and the fact that the costume is comfortable to wear, its not made of that clingy polyester material like most of the cheaper costumes you can buy in shops.