I guess that I'll be the one to disagree. The
DDP is a bargain for anyone who does TS meals everyday. But I think that you can definitely each cheaper without the DDP.
Each adult on the DDP will pay $39/night. You could bring breakfast foods to eat in your room, and do easily do CS meals for lunch & dinner for under $30/day. CS meals average around $10. Over a week's time, that adds up to somewhere in the neighborhood of $70 per person.
You also have to book a package with Disney to get the DDP. If you book just a room and buy the tickets yourself, you may pay less than you would for a package. You can get a room discount if you're a
AAA member (20% off the rack rate of a value resort room during January) and discounted tickets, like thru
UndercoverTourist.com.
I would check the menus and food prices at
DIS Dining & Menus to get an idea of what the food would cost. And then I would compare the cost of a package with DDP (you can price it out at
Disney's Official Website ), to the cost of doing room, tickets and food all separately. It's probably the best way to see which would work best for you.
ETA:
It's not that I don't like the DDP. I actually really like it a lot. It's just that I'm not convinced that it is the
cheapest way to eat while at WDW. Knowing how college students can live on PB&J for a week before they switch to mac & cheese the next, I think that the OP could probably find a way to survive at WDW for less than $39/night.