Veterans discount

Veterans and Military Purchase Program

https://www.apple.com/shop/browse/home/veterans_military

See if the above link provides any suggestions. If it comes down to it you can return what you bought and then instantly buy it again with the discount this time. ;-)

Apple Store (US) Sales and Refund Policy - http://www.apple.com/shop/help/returns_refund - "You have 14 calendar days to return an item from the date you received it."

To be fair, there's a lot of stuff a sales person can't always remember to ask, such as if you're a student, or if your computer at home is new enough to support the mobile devices you just bought, etc.