In an unexpected change to its “Buy a Mac, get a free iPod” promotion for educational customers, which runs through September 7 of this year, Apple will not offer students rebates on iPod models announced yesterday, a limitation snuck into a just-updated Terms and Conditions PDF on its Apple Store web site. Since late May, Apple’s web site has promised students and educators a free 8GB iPod touch or less expensive iPod model with the purchase of a new Mac computer, issuing up to $199 as a rebate after the combined purchase. Now, however, the new Terms and Conditions claim that the “new models are NOT ELIGIBLE for the Back to School promotion, and rebate “claims submitted in conjunction with these new products will not be honored.”

As noted by Macworld UK, neither the change in terms nor the way to take advantage of the promotion to order old models is obvious when viewing Apple’s web site. “Because the promotion says that you have to pay for the iPod first, then reclaim the money later,” a reader pointed out, “I suspect there might be quite a lot of disgruntled students in a few weeks time, when they discover that they’ve bought an iPod they really couldn’t afford and that they’re now not going to get the money back for it.”

iLounge has confirmed that this change is impacting U.S. customers who placed orders yesterday for new Macs and iPods, as the company’s telephone representatives are claiming that rebates—despite the lack of conspicuous notice during the ordering process yesterday—will be denied.