You can make a solar system model out of many types of materials. The one thing you should keep in mind is scale as the planets are all different in size.
DIY Solar System Models
How to Make a Model of the Solar System – Scout Life magazine
Exploring Space at Home - How to Make a Rotating Solar System Model
DIY Model of our Solar System - hands-on project for lower el students
How to make 3D Solar System Project for Kids
How to Make Solar System Models From Construction Paper
Make a Solar System mobile for kids
Solar System Model Kit Solar system model, Solar system projects, Make a solar system
DIY Miniature Solar System : 13 Steps (with Pictures
Rocket Launch/Create a 3D Solar system competition - Space Week
Build Your Own Model Solar System