Am I free to use these backgrounds in my project? It will not cost anything and I will provide credit to you.
Viewing post in Visual Novel Backgrounds (Premium Pack) comments
tl;dr : Yes you may use these backgrounds in your project.
License:
It is royalty free license, meaning you can use them for your commercial projects as many times as you want. Giving credit is not necessary but I would appreciate it.
But the backgrounds may not be distributed in the form that it is downloaded.