The lowest I've seen on a lot for the T-bird was $30k for a 35k miles basic black model.
When I worked in the Prudential Center in Boston I used to find reasons to go to the depths of the garage to take a peak of a robin's egg blue Thunderbird that was parked there by some executive.
Its a shame they were pretty rare since they did pretty well in the winter w/ the hardtop. A commuter at a neighboring town's train station used to own a red T-bird and had no problem traversing the snowy roads.
Oddly enough, the model of which it shares many components, the Lincoln LS can now be had for $4k-6k. Spare parts car anyone?