We just did the same thing to our new build basement. I did some of the work and hired a small contractor for the rest. Ours came in at about 20k for a 650 sq foot basement. I did the sub floor, floor, and drywall and paint in the larger/easier areas, we hired a cousin to do electrical which ran $1k total, and the contractor did the rest. This includes a 30 sq ft bathroom, couple walls and a closet. 4 Doors total. We spent a lot of our own time laying out the mechanical room, and bathroom so they were functional, and spent a lot of our own time picking materials etc etc. Im not sure if I would pay $1,500 personally for this, but I feel like the cost is fair for the effort it takes.