The three bid day shirts I remember from my chapter are:
1. When we were still a colony, we were on a shoestring budget, and another chapter had had a set of shirts printed where the printers left out a color, so they sold them to us at cost. They were a takeoff on Looney Tunes. Front: "Alpha Epsilon Phi Presents: Bid Day" with the head of a giraffe inside a couple of concentric circles (I think the circles were supposed to be red, and that's the color the printers forgot). Back: Porky Pig saying "Th-th-that's all folks!" Sisters could buy one at cost; I declined. UG-LY.
2. The following year, we printed our own. Front: picture of an American Express card with "Alpha Epsilon Phi" where "American Express" would be on an actual card, a giraffe where the centurion's head would go, and the date of bid day as the "credit card number". Back: "Membership Has Its Privileges" I bought this one.
3. The shirts my chapter has used for the past couple of years have a "Superman" design - the Superman 5-sided shape with the letters AEPHI instead of the S. Sisters and new members both wear them on bid day.