We have a yearbook. We give each child one for free. It is something we have been doing for about 10 years now. Although our publisher says it is bigger than any other primary/elementary school's yearbook, we think it couldn't be any smaller. It is about 70 pages. Everyone loves it! And we ususally have more than enough help putting it together.
I'm at the school where CrewChief was president and my friend is in charge of selling the ads. She said a business card size is $35, 1/4 page is $55 and 1/2 page is $75. We don't offer full page ads. Our yearbook price this year is $9. Our prices are all the same for in school families and outside businesses.
you probably know the size of the pages in the yearbook
decide on the number of pages you can dedicate to advertising
ask the printer how much it will cost this year to print
do the puzzle math to come up with how much you have to charge the different sized ads, assuming of course you can fill ALL the spaces - will partly depend on the size pages of your book
Then yu kjnow what to charge, whatever you need to cover the costs of priniting.
The math would be easier if you charged school families the same price as outside businesses.