Wow...what a lot of 'holier than thou' posts!!! You'd think none of us own a Mac laptop, phone or tablet...Sheesh!
$2,000---and it's 'extra' and you NEED a decent computer/smart phone for college, I'd say get both! The Air WILL last you through your next 3-4 years of class (assuming you've got that much left), the iPhone integrates perfectly with your Mac---and is much more portable when you're out and about, easy to jot notes down, use Pages or Numbers to update documents, PDF apps for your school papers, EBooks and Kindle, Nook, the Apple Book Store and TED, man...the list goes on and on and on!!!
The only suggestion I'd have is to also try to squeeze an iPad in to that $2,000! That's just me though
Having a working laptop while in school that you don't have to worry about 'working' when you need it to---a smart phone in this day and age is a 'must' and will be handy as heck @ school....the latest versions of each (MBA and iPhone) are exemplary products.
Sure---a good life lesson, "It's not what you make---It's what you 'save'" but right NOW---you're learning your craft, turning in assignments, writing papers and doing a LOT of reading...research, labs, et al. There are so many excellent apps available to those in 'school' right now---to me, it's unimaginable to not have access to a working, competent computer/laptop and a smart phone you can count on.
When you start working in the real world, start saving. That's an excellent idea....realize your computer and phone aren't investments, but tools. Just as a carpenter needs his hammer and nails---you, as a student, need the appropriate tools to do your job, and do it well and efficiently without headaches associated with a broken, old Window's laptop. Once their on their way 'down'....it's tough to recover that original 'speed' and stability (I'm a 25 year Windows user).
Good Luck---But buy what you feel like you need. No more, no less...and expect these types of answers on a board that is populated by many of us that didn't have access to this type of technology @ this PRICE in our days @ university

When I was in school, a good laptop was close to $4,000, desktops--- $3,000 and there wasn't 'smart phones'...only $3,000 Motorola bricks with $2/minute charges to talk...forget data and texting
J