I've done this twice, completely on my own
The first time I went w/o parents was June 2007 with my best friend, we did it with the
DDP so that EVERYTHING was completely paid for and we wouldn't have to worry about money while we were there (of course we brought spending money). At this time they only had the regular DDP, but I believe that they now offer the quick service one which is a cheaper option...
Anyways, I chose to do that because I KNOW the friend I went with is really bad with money and CHEAP, so I know she wouldn't bring enough money w/ her and therefore she would barely eat and be hungry and TIRED from not eating. And I was right, because she wouldn't even buy water bottles at the parks (hot, June weather!) even though she was thirsty, so she ended up getting heat sickness and being dehydrated and throwing up etc.
So...getting a plan with a food option might be a good idea because that way you KNOW you don't have to worry about paying for food once you're down there. And, it obviously also includes the hotel, magical express, park tickets, and Disney transportation. We stayed at All Star Music. My mom's friend charged it to his card for us at
AAA and we both just gave him $100-$200 weekly until we each paid off our half of the cost, but I think if you work with any
travel agent you can just give them cash or whatever until the 45 day mark (I think that's the point where it has to be completely paid off!)
The 2nd time I went without parents (or money help from parents) was this March in Spring Break with my boyfriend. We ended up getting a 40% off pin code for the hotel, so we didn't book a package because it saved us a bunch of money. We also were pretty frugal with the flights...booked CRAPPY flight times to save $ (like 6am times...). However, once we got there we ended up just splurging and dining out at full service restaurants even though we didn't have DDP (without the DDP pretty much any table service meal for 2 people is going to cost $75-$125 at most places on property...our cheapest TS was Sci-Fi at like $60 for 2 sandwiches, 1 frappe and 1 specialty alcohol drink thing...) If we ended up being pretty frugal with our dining and spending once we were in FL, the trip probably would have cost us about $2k total but it wound up being around $3k since we went all out on meals, shopping and entertainment, doing things such as renting Sea Raycers and we got a taxi to the hotel from the airport instead of ME because the line was SOOO LONG and we didn't want to waste that much time since it was a short (4.5 day) vacation to begin with.
Anyways...those are my 2 experiences doing this. My job is waitressing 3 days a week and that usually brings in about 400-500 a week with my monthly expenses being about $700
Sooo to summarize since I KNOW I rambled on a lot in this post..
You can either do a complete package with whatever dining plan you want, which is helpful because that way you don't have to worry about money for anything except souvenirs and water/drinks once you get to Florida. You'll probably have to pay for this by 45 days out though.
The other option is to shop around for pin codes on the hotels, this might save you a bunch of money on the resort (this is why we did this in March since the discount was 40% off) and basically book everything "a la carte".
The reason I chose to stay on-site both times was because of the not being able to rent a car yet issue too. Technically I could have with DBF this past March since he was 24, but most car rental places charge a TON extra for people between 21-24 and you only can get decent rates if you're 25+, and he wasn't 25 yet. But I looove staying on-site anyways since Disney is all we were planning to see both times.