In FAA-land they can use "PCATD" sims for part of the IFR training - nothing more than a fancy PC-sim with a letter from the FAA authorising it. I didn't find that it added much value - but the school charged peanuts for it (I think you just paid for the instructor time) and it counted towards the hours requirement.
In 2010 the school I was at was charging (I think) $82 per hour for an instrument-capable C152 plus $60 for the instructor. I wonder how much cheaper a decent sim would be?