Adobe: Students and teachers can get 60% off Creative Cloud.
Apple: The discounts change over the year, but you can generally get slightly cheaper laptops and iPads. They also offer occasional back-to-school deals, like free Beats headphones with a more expensive purchase.
Amazon: With a .edu email address, you can get Amazon Prime Student free for six months, with a $10 referral bonus for each friend you can get to sign up. After your six months are up, Amazon Prime costs only $49 per year instead of $99.
AT&T: Check if you're eligible for discounts on a plan by entering your .edu email address on their discount page.
Dell: Students get 20% off PCs in the online store with other discounts that change year-round.
Lenovo: Discounts vary by item and where you live.
Microsoft: Students and teachers get 10% off, with other deals offered year-round.
Sprint: Check if you're eligible from their Discount Program page.
T-Mobile: T-Mobile offers up to $60 off smartphones and 20% off phone accessories for students and teachers.
Verizon: Verizon makes their discount hard to find. Go to their discount page and scroll down to "Not yet a Verizon Wireless customer?" Enter your .edu email address where it asks for a "work address." They'll email you and tell you if you're eligible for a discount.