Be careful using the words "copyright release". You could wind up not owning the photos you make.
I suspect you mean a Use License, which is often termed a Print Release by retail photographers.
A use license/print release is like a rental agreement. You still own the photos (copyright), but allow some other entity to use your photo in some way.
For retail photography the usage is usually a personal use and the use license/print release does not allow any commercial usage.
How much you charge for photos has to based on an amount that lets you pay your business expenses. So step 1 is to determine what your Cost Of Doing Business (CODB) is.
Other photographers will have a different CODB from yours so their pricing structure would not necessarily work for you.
Yet another pricing consideration is the client demographic you direct your marketing to.
It may help to realize that having paying a photographer to take pictures is a luxury expenditure.
There are several different pricing models.
Loss leader
A La Carte
Sitting fee with a print credit
Packages, plus the sitting fee.
By the sheet
By the pose
The list goes on....
Or some combination of them all.
Prints are usually priced by size, in so far that as prints get larger so does the price.
Prints can be made on different media too, like c-print photo paper, metallic c-print photo paper, inkjet paper, inkjet fine art photo paper, canvas, acrylic, aluminum, etc.
So an 8x10 on regular c-print paper would cost less than the same photo on 8x10 metallic c-print paper, and the same photo printed on an 8x10 canvas would cost more than an 8x10 print on the metallic paper.
For digital image files on a CD/DVD many retail photographers require a minimum purchase before clients qualify to buy a disc of images.
Since digital images on a disc can be printed by the client at many different sizes, an average price is often charged for each digital photo file, say $20 to $50 per image file.
