Appendix ponies come in all shapes and sizes. Mines an appendix (avatar horse) and she looks pure quarter. A friend's horse is also an appendix, and he looks like a gigantic grey tb.
As the others have stated, you can find a very decent horse for $5000. From a well bred green warmblood to a well broke, all around grade...theres a lot of nice animals out there for that price. The idea is to find someone you like. Try them all out and pick your favorite. None of my horses ever cost me $5000 and they all did exactly what I wanted them to do.