It's still too early for you to give up! I got my girl when she was 4.5 months and paid $600 for her.
Before her, I had actually found one I was interested in who was 2 years old, 5 lbs, 1 ear up, 1 ear down, and spayed being rehomed for $450 and it was coming from a many hour drive from where I lived. Unfortunately, when I called to confirm the night before we were to meet up midway between us already with location set, etc, the couple had chosen to rehome her to someone local to them who already had a male yorkie.
I had also expressed interest in an older boy located in Portland, Oregon. Apparently, he was a bit of a barker, and needed rehoming because the owner didn't have time for him. I forget the cost of the rehoming, but it wasn't far off from what you're asking. Again, someone else beat me to it.
I loved the look of this guy. He had the whole butterfly/bat-ear thing going.
The above were all from ads found on Kijiji.
Yorkies and mixes in my area are fairly quick to sell. Sometimes it takes a little longer, but if they were priced as low as yours, they'd definitely sell no matter what the parents of the pups looked like as people just want a relatively inexpensive toy breed as their family pet. This may also be why so many end up in shelters.
But the point is, with the right buyer, they all sell.
I guess it depends also on where you live.