DH and are are APs and try to go about once a month--- we stay at cheap places to be able to do this. We have the most success checking on Groupon, Living Social, and
Amazon Deals to get pretty decent places at great prices (usually try to stay at about $50-65).
We found a "go-to" place that way (Destiny Palms) that we go to when we can't find a better deal. It's about 15 min from Magic Kingdom parking lot. Its clean enough-- the carpet is kinda grungy.... but that's what I expect when I pay around $39-49 a night (depending on the time of year and deal site vs. Priceline, etc.). We've gone there about 6 times in the past year and we basically just sleep there and spend our time in the parks. FYI: the breakfast offered is awful, but there is a McD's right out front LOL
Another place we found that way that we liked was Maingate Resort and Spa (maybe about 7-10 min from MK parking lot)... still have yet to find the "spa" part....

Anyway, it's much nicer than Destiny but I found it on a deal website and not sure what its rack rate/ Priceline/Orbitz rate is, but certainly more than Destiny. But it's recently refurbished and clean!
All others in that price range that I have researched have looked much grungier, but I haven't actually stayed and couldn't give a fair evaluation. But it all boils down to personal opinions and what you are willing to tolerate to stay cheap. For DH and I, we would rather go every month and stay cheap than only get to go once every 2 or 3 months by staying in nicer but more expensive villa or something. But that's just us!
Hope that helps!