Build the largest 'square' box that fits in the space. It saves a load of ballache especially with shelves. Make a plinth to level it too.
Price varies madly depending on materials, finish quality, interior fittings, location (in the country) etc. A quick and dirty version unpainted in thin MDF is a couple of days work. Upwards from that could be anything!
Scribe to the walls, yes. It depends on the design. It can end up being seamless with the wall. You can have a door surround or have the door encased. Lots of subtle design choices.
Build the largest 'square' box that fits in the space. It saves a load of ballache especially with shelves. Make a plinth to level it too.
Price varies madly depending on materials, finish quality, interior fittings, location (in the country) etc. A quick and dirty version unpainted in thin MDF is a couple of days work. Upwards from that could be anything!