GIMP is an amazing free editor that can open most of a PSD file. Unfortunately one important thing that GIMP cannot do inside of a PSD file is read font layers. Instead they are rendered as a regular image layer making them unable to be edited.
To get the full functionality and flexibility of our templates you will need to make modifications to the Photoshop files (PSD). To properly modify these you will need either Photoshop CS3 or higher or Photoshop Elements 10 or higher.
If you do not have either we recommend that you pick up a copy of Photoshop Elements 14. You can find it usually for less than $80, and sometimes for $60-$65. Use the following link to find it on Amazon http://amzn.to/2bCQS30.
Adobe also has a great Photography plan for $9.99/mo that will get you Photoshop. You can learn more at http://amzn.to/2o9um4z.