here is a textured city for 89$:
http://www.turbosquid.com/3d-models/3d-city-skyscrapers-model/480825i didnt bother to look for even cheaper citys.
Its ok for you to ask whatever Price you imagine, but offer a model with small pictures and nearly none information will not help you sell your models.
Plus raising the price from 50 to 500 just to texture your model is way to much, but i hope to know that urself
again, its ok to ask any price, but dont expect alot of interests here, after all its stil indie-area here!
Nice Day