There will be plenty of conflicting information, but honestly if I were to advise you, I would say shop around for your flights, and stay on site in the cheapest hotel, this may seem expensive but it saves you having to have a car so you don't need to worry about the deposit for the car, the insurance or car hire (really depends how you do it- if you get a "free" car the insurance is more expensive than the whole thing through car hire companies. As pp have said $20 a day parking too!
Staying in a villa means another deposit, $500 once we've paid- we will get it back but it means we've got £900 put aside for deposit on car and villa which we could've put into dollars otherwise.
A lot of people are split on this, but I think dining is worth adding to your booking. You don't need to worry too much about food then, you get snacks and you get a refill cup to take around with you.
Plus staying onsite you get bands which are otherwise $20 each.
They also allow you to book for a small deposit £150-£250 and then pay as you like until 14 weeks before you go.
I booked flights &villa through Thomas cook, tickets through Orlando tickets, car through enterprise. It's worked out more expensive than staying on site which is what we will do next year.