Go to Toys 'R Us. Among others, they have a kit for kids to build. The wood is pre-cut and it comes with all the material you need to make it. I think it's like $10-12. Maybe even Home Depot, itself, carries it I don't know.
If you'd like, go to Wick's Weekend Warrior's Page, click the link for 'Plans (BBQ, Woodworking, etc.)', and visit the listed links. My best to ya and hope this helps.