I have used an app called PicFrame that I found in the app store and have used for a long time to make collages etc.
So, when you click on the app this is what you´ll see. For this project you will want to choose the square frame.
Click in the frame to choose your photo.
The when you click your photo again this menu will appear. Click shape.
Now you can choose whatever shape you´d like to crop your photo into. I choose the circle option.
Tada! Now, just save your photo, transfer it to your printer and you can either print one bigger circle on one photopaper sized 6x4 or more smaller ones if you have the option to print multiple images on one paper. This way you save ink since you don´t have to print the whole images and the just punch/cut one portion of it.
I hope this little tip is useful!