At that budget you're probably looking at a 10 year old coach at a minimum. Concerns at that point become things like: viability of the appliances and motorhome equipment, whether the class C body seams are intact and haven't leaked, condition of the roof and serviceability of the engine / availability of engine parts.
Not sure you'll find two slides on <24' coach of that age. My advice would be to set up an advanced filter search on www.rvt.com
and tune it to your budget and length restrictions. See what comes up. The forums can help with brands, bad engine years to avoid etc.