Equine now.com & southern california horses for sale & lease
what kind of horse do you have and where do you live
I think equine.com is a good site. Sold and bought through this page.
Equinenow, Horseclicks, Equine.com, Dream Horse Classifieds... Facebook groups and private pages are also good. Craigslist sometimes has a solid horse, though naturally it might be a little sketchier. Happy hunting!