I was going to see about a relative junker as well, but after looking at what people were selling, I decided to just hold off purchasing anything until my vehicle is paid off later this year.
Under $40k, the rigs I encountered were quite worn, with (as mentioned above) any front facing windows having a leak.
By raising the bar to $60-65k, I can find a new Ford E-350 unit, likely a corner queen with a dinette slide. Nothing worth writing home about... but for a single person, would be a reasonably serviceable unit, especially after adding 250-500 watts of solar, and some other upgrades (Shur-Flo 182-200 accumulator tank, for example.)