Well, it hasn't been that long since I've been a college student and now I teach college students, so I am still "in touch". At least I like to think I am.
First, I would drive down if possible to save money. I didn't notice where you were from, but usually driving saves LOTS of money. Although if you can get a good deal since its only the two of you, it might not be so expensive.
*edited. I just saw that you are from Canada and driving might not be the best idea.
Second, I would stay off site and bid for a hotel on priceline (another reason to drive so you can have the car). I remember what kind of places we stayed in when I was in college, so I think you can bid on a 2* and up and be happy since it will only cost around $20 a night.
Third, go during VALUE season if you stay onsite. This will make your onsite stay cheaper, even without codes, etc.
Fourth, buy tickets before you go from a ticket broker. There are many recommended places on these boards. And you don't need to buy a ticket for each day you plan to be there. You could plan on spending a week at WDW and get a 4 day hopper PLUS. Spend 4 days at the parks and one day at a water park. Then spend a day or two exploring the resorts, etc.
I think college students would like Disney Quest (but that costs extra unless you have an ultimate park hopper). I think you only need to be 18 to get into Pleasure Island to dance (but you wouldn't be able to drink) so if you like clubs and things that is another option. Walking around the boardwalk is fun and free (provided you can control yourself with buying stuff). Also a water park like Blizzard Beach (costs extra unless ultimate park hoper).
If you like thrill rides, try MGM. That seems to be a favorite with teens/college students. There is Tower of Terror and Rock and Rollercoaster. You may also like Star Tours. Potentially Indiana Jones, if nothing else but for the "cheesiness factor".
If you like to explore different cultures, I think you would like EPCOT. Plus Test Track is there and Mission Space, so those are thrill ridey too.
Go to Magic Kingdom just for the Disney factor. You would probably like Big Thunder Mountain RR and Splash Mountain. Also Space Mountain and Buzz Lightyear.
You probably wouldn't be so into Animal Kingdom.
You can eat counter service pretty cheaply. Burgers/fries and drinks run $8 or so. If you decide to try a sit down place, you can always order an appetizer and entree to share. Or get a pizza to share at Mama Melrose in MGM, etc. You can get a rotisserie chicken meal at Cosmic Rays in MK for cheap and share that.
I'm not sure if this all makes sense. I am just randomly throwing things out there. One thing I do know is that "Real Life" approaches very quickly. Take this time and enjoy it while you can.
Maggie