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!
It makes a huge difference. I guess the only reason not to do it would be material cost if you were DIYing. If it's a professionals time you're saving then it's worth it.
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!