Terranscapes is expensive!
I didn't think they were that expensive considering that the majority of their stuff is assembled and painted. The castings are with ultracal 30 which is an expensive alternative to plaster but much more durable. Think about how long it would take you to create the halfling house, put it together, paint and flock it. How much an hour do you want get to paid?
I'm actually considering starting an online terrain store using Hirst Arts but I was going to concentrate on smaller items at first, like a rock or block fence, building it in straight and corner sections then recasting it with resin and selling them both unpainted and painted. My goal is to do pieces that would cost less than $20 even the painted ones.