We highly recommend going to your local art store to purchase the materials you will need for your prop making. You can either purchase an authentic version of this helmet at a cosplay store online, or make your own using materials such as paper mache or foam. For your Harry Potter cosplay, we can see that Taobao and Aliexpress both sell the wands but if you are on a budget, you can simply make one yourself using a wooden chopstick, a glue gun, and various shades of brown paint.