I almost panicked at the Grad Fair my school had- I expected high prices but I hoped to get 10 invitations with photos for not more than $70. The closest package to what I wanted added up to $92.57. Also, up close the announcements didn't look fancy like I expected- the school seal was a sticker, the font was curly instead of classic, and the free edge of the cards was frayed to show the thick paper. (I think this effect looks good on artistic stuff, just not something that should be classic) So I decided to make invitations from the fliers I got at the Grad Fair.
Scavenged Materials: Price Sheet for Graduation Announcements, Commencement Brochure, and a Campus Map
I circled the relevant info on the brochure. Most of the brochure was important info for guests, or gave a cool atmosphere by showing what I have to do to get ready, but part of it was cluttered with things I "should" buy, so I papered over it with my handwritten graduation announcement.
(I copied the sample text from the Price Sheet.)
Put the announcement on the flier diagonally, so that all the corners are within the edges of the flier, and fold all the edges over crisply, leaving the top flap for last.
I folded some envelopes to take advantage of the color printing in my school colors, and some envelopes to show the package prices as an implied explanation for my handmade invites.
If you have glue, a pen, and stamps on hand these are free and the info on the found materials makes this a very quick project. I wouldn't really recommend this if you have more than a few invites to send, except now that I think about it I came at the last hour of the last day of the fair, so these were probably going to get tossed.