First think about our major and what programs if any you will run throughout your college. Here at A&M each major has the recommendations for laptops somewhere on their website. Macs are great computers but they aren't always practical. For myself a Mac is perfect, I'm a business major so I don't run these complicated programs like my friend who's majoring in chemical engineering. The reason I say look at what you'll be using is because a lot of companies that make the more complex programs don't favor Apple, which in turn leads to you just having to download a second program just to run the original. If you're majoring in anything with engineering, programming, etc. go with a PC.
As for the discount, I did the discount when I bought my mac. The discount only applies to the brand new computer not a refurbished model. Be aware that the discount isn't anything to go crazy over as you'll only save $50 and only covers certain models. If you can spend $850 not including tax then you can get the 11-inch lowest model air. when I bought my 13" it totaled out to be $1100 and that was with the discount. But don't just limit yourself to the Apple store. My girlfriend went to the best buy across the street from the Apple store a week later and got the same exact computer for $950. Also both best buy and apple finance. In the long run you may pay more but it would be an option if you're dead set on getting a mac but can't drop the money all at once. Last option is just unfortunately purchase a cheaper non apple computer