There are no stores that sell a Gru nose without also selling an entire Gru costume. Instead of purchasing a premade nose, users can make their own noses by purchasing nose putty from Amazon.com or Ziggos.com
To mold nose putty, begin by cleaning the face and pulling the hair back. Apply a coat of spirit gum to the nose with the bottle's brush, and tap the spirit gum every now and then until it is sticky. When it is sticky enough, apply small amounts of cotton to the surface to provide the putty with a fiber to which it can adhere. Once the cotton is in place, shape the nose out of the putty and then let it dry.