I would definitely look at AirBnB and VRBO.com. And maybe also temporary/sublet listings on craigslist.
Tons of vacation rental units in the greater Orlando area. I've rented a few by the week for relatively cheap - but I always have a huge group, so I've been dealing with larger houses.
Hotels/motels can also be SUPER cheap. I've stayed in hotel rooms in Orlando for about $30 - $45 a night --- in both shady hotels and nice timeshares just by searching my dates through kayak.com. Priceline and Hotwire can also turn up good deals. If going the hotel route, you will get the best rates by being willing to move every few days to take advantage of whatever establishment is giving the best deal for each day.
ETA: Hotels in the "East Gate Area" of Disney have generally been my best bet. But, if I'm going to Orlando, I'm going to Disney. Feel free to face-punch me, but I heart Disney and am not ashamed. The further you go from Disney, the better the deals until you get so far away that they aren't catering to the Disney crowd.