The bids we used when I got mine were about the size of a thank you note, on really good paper with a golden crest on the front. It read: "The Sisters of Alpha Iota Chapter of Alpha Delta Pi extend their bid to Honey, in the hopes that she will meet the requirements of being initiated into membership."

So it was clear from Day One that you didn't dare slack off and still get initiated!

Then, for a few years, the Panhellenic issued bid cards, with fill in the blanks - very tacky. Enough people must have complained because they're back to the ones our EO issues again (or, when last I asked).

At USC, every sorority I've dealt with gives the same bid card. They read:

"The sisters of the [GLO] chapter at the University of Southern California invite you to join them in the bonds of sisterhood and the joy of lifelong friendships. Welcome to the Greek community! Fight on!"

The crest is on there as well.

Thanksgiving
 

My mother handed me a box of "stuff you might like to have" when I got to her house for Thanksgiving weekend.

In it was my bid card!

No scanner here at her house; I'll post a photo another time. It's a simple white card, with the sorority name handwritten on it. There must have been a separate reply card, though it was a loooonnnnngg time ago.

my bid was a cardstock card with the Chi Omega crest on it and said "Chi Omega has cordially invited [name] to become a New Member of the [chapter] [school]" then signed by the president and recruitment chair
and as far as I've seen all the chapters at my school have a very similar bid

At UF, Panhellenic dictates that all bid cards are identical. You can't even use ink that isn't black or blue if you want to follow all the rules. So you write in the woman's name, the chapter and sign the cards. Its kind of sad. I would have loved one with my chapter's emblem(s) on it!!