Have it in your backyard or at a local park. Make a theme he likes; Pokemon, Teenage Mutant Ninga Turtles, Spiderman etc. you can buy party packs (paper plates, napkins cups etc) quite cheap. Decorate with balloons and have a themed cake. Play good old fashioned games, kids love them until at least 11. Musical statues, musical chairs, limbo (use a broom stick), face painting, balloon games etc.