Hi Hilda,
A birthday trip is so special! Your son is very lucky.
Hilda, my first question is: is it critical to be there on the day of his Birthday, or can you do it a few days later? At this very moment, I currently see some specials on the Disney
Special Offers page which start a few days after his birthday. Offers change frequently (and fast - so fast that I hope it is still there when you read this!), so keep an eye on that special offers page, and book as soon as you see something that suits you.
Also, our family loves the
value resorts which are the least expensive of all the resorts. They are SO much fun for a six year old and a really great value for our money.
If you are open to traveling at other times of year, January and also late August through the third week of November are considered value season (the best priced time of year).
I hope some of these ideas help...please let me know if I can answer any other questions.