"Less expensive" is a relative term. When looking at off-site options, be sure to factor in things like airport transportation, parking fees, and/or resort fee. (Those things will not apply to every hotel.) You also need to investigate the shuttle schedule. Many off-site hotels only provide 2 or 3 trips each way to Disney World. Additionally, many only go to one theme park (usually Epcot). From there, you have to use Disney transportation to get to other locations.
Personally, I'm a fan of the hotels at Disney Springs. These seven hotels are on Disney property, but are owned and operated by outside companies. They share shuttle buses that run every 30 minutes all day long. Each bus goes to two theme parks. Usually, one goes to Epcot followed by Disney's Hollywood Studios. The other goes to the Transportation and Ticket Center (monorail/ferry to Magic Kingdom) followed by Disney's Animal Kingdom. The system isn't as convenient as Disney resort, but it is a vast improvement over most off-site hotels.
Disney Springs Hotels Marketing Website (including some discounts):
http://disneyspringshotels.com/
As you search for prices, make sure you're comparing apples to apples. Lots of people seem to compare Disney's Value Resorts with off-site hotels simply because they are generally comparable in price. That's problematic because the Value rooms are tiny motel-style accommodations and many off-site hotels are must nicer.
As an example, I picked a random date in July (7/13 for 5 nights) and priced out my favorite Disney Springs hotel, the DoubleTree Suites:
- Disney's All-Star Music/Movies/Sports: $160/night
- Disney's Pop Century: $176/night
- Disney's Caribbean Beach: $210/night
- DoubleTree Suites: $132/night using discount from the website above
At the DoubleTree Suites, you'll get a 540 square foot, two-room suite with two queen beds and a sleeper sofa. Unlike Disney's Value or Moderate Resorts, all room are interior entry and you'll earn frequent guest points through Hiltons Honors program (free to join).
Feel free to ask any questions. If you can provide more concrete dates, I'll gladly search more options.