My daughter is a Senior and it is crazy.
Blunk's Photography did the traditional photo for the yearbook (free) with the "tux" and "drape" for the students back in June. They give everyone the proofs and you order if you want to. They are pretty pricey.. I am getting a very small package just for gifts and it is over $300
We are having personal senior pics done soon as ( when the $400 Varsity cheer jacket arrives). I use Alex Lee H-D Productions. He does all of the shooting for the sports teams and has captured some great shots of our daughter. He also did the prom shots for us in April.
I think the students decide how many invitations they want and order them when the order the cap and gown (not positive about that)
I don't know how some people are keeping up with it because it is very expensive. Every time I turn around it is $100 here $300 there. Fortunately we are sound enough to cover it but I feel for a lot of the families going through this.
Get creative with your pics and invitations. Do you have a friend who is a good photographer? Find a good spot and start shooting pics! Same with the invitations, look online and design your own if needed.
If you are like us... your mailbox is FULL of advertising of photographers and college info.
Good luck to you and your son... the time has certainly flown by.