You can directly purchase a P-body Portal gun replica on the Internet. Of course, if you wish, you can also following the crafter’s steps, and making your own Portal Gun by yourself.
This is an awesome homemade replica based on Portal Gun, the iconic weapon in the universe of Portal video game series, and homemade by backwards lamb. As we can see from the image, the replica features subtle details and beautiful colors from the original portal gun, you even can see gorgeous light effect. The maker used various material to build the Portal Gun replica including blue insulation foam, PVC pipes, tube, plastic acrylic shell and more, and all the steps have been released. If you want to make your own Portal Gun, jump to instructables for more details.
Additionally, if you have no time to do this, you may like to check the P-body portal gun replica.