My Chapter Association has done this before (not an alum chapter, but an org made up of all the initiates of a specific college chapter) & it went over really well.
You can get some great things, really cheap, in bulk from
Oriental Trading Company including some candies.... Here's what we included:
Smarties & Twizzlers
Chocolate kisses (for that little caffeine boost)
peppermints (to wake their brain up)
stress balls or bouncy balls for when they needed a break
colorful maribou stacking point pencils (3.49 a dozen from OTC)
OR DZ pencils (OTC has some really fun pencils to choose from)
2 scantrons each & 1 blue book (they could trade with eachother if nec) (one of our alums was on faculty & could get these for us for free).
Small bag of chips or pretzels (bought in bulk from Sam's)
Hot chocolate or instant flavored coffee packets
a coke
We bought the gift bags for them in bulk as well from
MrGiftwrap.com
The alums who were in town assembled the bags before the last chapter meeting & distributed them then. From what I hear, the chapter really loved them...and if you buy the stuff in bulk, it really isn't that expensive at all.
I know some alum chapters do this as a fundraiser--they contact the chapter member's parents early in the semester and sell them for $X...to make sure that all the girl's get them, if their parents don't buy, some of the alum chapter members buy them for them....