What age group is this costume for?
Elementary School

Estimated time required to make this costume:
Less than an hour, other than shopping time.

Difficulty level:
Quick and easy - no sewing required

Items you will need: (Hit your return key to start a new line)
FOR ASH:
Jeans
White t-shirt
Blue vest
Red hat
White and black felt
Teal gloves

FOR PIKACHU:
Yellow sweatshirt and pants
Brown, black and yellow felt
Yellow pillowcase
Yellow yarn
Red lipstick or face paint

Instructions:
The only thing I had to make was the hat. I bought a red baseball hat, cut white felt to fit the front section and glued it on (or get sticky felt). Cut a Pokemon league symbol from black felt and glued it on. The only other items to adapt are the gloves, cut the finger tips off the gloves. The rest is either clothes from my son's drawer or bought from Good Will.

For Pikachu:
Cut oval stripes from brown felt and glue or pin to sweatshirt.

Cut a lightning bolt shape from yellow felt, glue brown stripes to end, Pin to sweatpants and sweatshirt.

Cut a hole for child's face in pillowcase. Bunch up corners and tie with yellow yarn. Glue black felt tips on "ears." Paint round cheeks on child's cheeks with face paint or lipstick.

I also cut lightning bolt shapes from leftover yellow felt and glued to the sleeves of sweatshirt so my little Pikachu could look like she was throwing bolts.

Other information to consider:
If you pin, rather than glue the felt items to the Pikachu sweatsuit, your child can wear the suit again as regular clothing.

Add a few Pokeball toys or cut Pokeballs out of posterboard and tie to "Ash's" belt.