Not sure if you wanted on or offsite...If onsite - I likely would rent points as pp's mentioned. You can do it within that budget.
If offsite - One of my favorite places that will be well BELOW your budget is Staybridge Suites Lake Buena Vista. It has:
AWESOME location
Clean pool and laundry area
great staff
Full, HOT breakfast included every morning (This is the part I like better than renting an offsite condo - it makes it feel like vacation to me to be able to just tell the kids to go eat downstairs and it's all done for us.), including eggs, sausage, cereals, waffles, muffins, juices, coffee.
Rooms have kitchen which work great for grabbing dinner on the way back to your room.
You can get a 1 bedroom for likely $99 per night and a 2 bedroom (great if you have kids) - for maybe $125 per night.
This is my preferred offsite location. Love it here.
Another thought: Swan/Dolphin. We stayed at the Beach Club on our most recent visit and I don't think I'll stay there again (beautiful but the location was the best thing for the money). So to get a similar location we're thinking of trying Swan/Dolphin next time. If you are big EPCOT fans, this might be a good choice. It should be in your budget too.