I did the same thing with my friends last year. A few things to consider:
1) If you have a long winter break, take advantage of that. Going during Spring Break will be a fortune, and you may have internships for the summer. Early January at the very beginning of value season was cheap, plus we still got to see the Christmas decorations even though the events were no longer going.
2) Can the 4 of you stay in a single value without killing each other? It will be full-sized beds and one bathroom, but the sink at our room in the AsSp was on the outside of the toilet/tub so we were able to get going quickly. You'd save a decent amount of $ there.
3) Do Disney transportation the whole time, ME, the busses and such. We're too young to rent cars, or if a group does give us a rental, its a fortune. If you're driving, never mind.
4) Pick a clump of time that's as open as you can, then watch for Southwest and other airline sales. We went during our break, and were originally doing an earlier departure but then a Southwest sale came out that started for flights on the 7th. So bumping our entire trip back two days didn't matter because we weren't fitting it in anywhere.
5) If they've never been, you don't really need Hoppers because they will be able to spend an entire day (or more) in each park seeing all there is to see. If it's winter, you don't need waterparks. So I would just go base tickets.
6) Keep an eye out for promotions for the dates you are planning on. We were originally going to do 5 park days (2 epcot) and no parks on arrival day, and we ended up finding a promo where two of our hotel nights were free and we got two extra park tickets, so we added a day to our trip and spent our arrival afternoon in a park.
7) Don't bother with
DDP. Bring cereal/granola bars, etc for breakfast and pay OOP. The portions are so big (you know that) and its not like you're doing 10 character meals for little ones to make the cost really worth it. I think you'll save money. If you feel like doing some TS go for it, and try doing it for lunch rather than dinner since its cheaper.
8) If your friend really doesn't want to go, I would suggest you respect your feelings. Not saying cancel your trip, but don't force anybody to go to Disney who doesn't want to - they'll be a wet blanket and make everyone miserable, particularly if you are sharing a room.
That's what I learned, at any rate. Best of luck planning! I think I ended up going for about $450 per person plus food and souvenirs at double occupancy for a week, less for quad but I don't remember how much. I don't remember if that included airfare, I don't think it did but I found the deal as I said so that was barely $100 RT The friends I was planning for balked at even that much. I don't know what they were expecting as I got it as low as humanly possible, but I didn't let the fact that all 8 people we had proposed this trip to shut me down bother me, just grabbed my boyfriend and we had our own trip without. Don't get discouraged, we're all frugal college students, but some have pretty outlandish ideas on how cheap a vacation should be.