the escape package starts at around $4750, i think, may be more expensive for the wedding pavilion and the canada pavilion.
The escape package includes the basics of what you need for a simple disney wedding, floral for bride and groom, violinist, limo, cake, champagne, photography, etc.
you are required to buy more drinks for the champagne reception if you have more than 6 guests [correct me if i'm wrong anyone!]
you also need to stay 2-4 nights in a disney resort.
aside from the above, you don't need to spend any more money on your event. you will have your ceremony, then a cake cutting ceremony with champagne.
if you want, you can then go onto any of the disney resort restaurants for a meal, or you have arrange a reception through disney, but this will trigger a $7,500 minimum spend.
if you want any extras such as characters, the Magic Kingdom photo shoot, a dessert party or more, then that is when the costs start to stack up!
i would recommend buying carrie's passporter guide to disney weddings and honeymoons, as it will have all the information you are looking for!