I agree with what everyone else said--we live as frugally as possible, and I do lots of little things that make extra money for us. I think having no credit card debt is key. We were in credit card debt at one point, then we finally bit the bullet and didn't go on a vacation for four years (or do anything else fun, for that matter). However, we paid off all the credit cards and learned a very important lesson along the way--how to live within (and below) our means. It has literally changed our life. It's unbelievable how our income has gone down about $25,000 a year (I went from working full-time to working part-time), yet we're in better financial shape then we were when we both worked full-time. I view saving money as my second job. I'm willing to go out of my way to get a good deal. I buy all my kids clothes a year ahead. We drive a 98 Nissan (3 more payments to go

) and an 89 Honda. Although we could replace the Honda in a few months, we've decided to keep it as long as possible and keep saving in the meantime. I'm hoping we can pay cash outright for a good late-model used car.
To help pay for this trip, I've done reward programs (like My Points), mystery shopping, online surveys, in-person market research groups (I've got one next week for $100, and DH has one for $150--good week!), selling on Ebay, rebates, test drive incentives, charging everything to our Disney Visa....all these things add up. For our upcoming trip, I've saved hundreds of dollars in cash, I have $260 in Disney Dollars (from the credit card, and also from test drive incentives I was able to convert to Disney Dollars), $50 Rainforest Cafe gift certificates, $25
Walmart gift certficiates (for film developing when we get back) and a $50 Cracker Barrel gift card (for the drive down). Just wanted to give you an idea of what you can accomplish with some time and effort.
OP, you didn't state how budget-minded you are, so I hope we aren't "preaching to the choir" here. Hopefully we've given you some new ideas, though. There are many websites out there devoted to helping people find "deals" and save money. If you're interested, feel free to send me a private message and I'll email you some links. Hope you get to Disney soon!