Thread: Why are DC-DC power supplies so expensive?

How come it's so expensive to build a DC-DC power supply that can only provide power to a small range of CPUs and to a limited peripherial configuration, while an inverter can power just about any PC configuration for a lot less money?

I could understand a DC-DC PS costing little more ($10-$50) than an inverter, but it seems that these PS's cost about $100+ more than inverters. Why such a discrepency?

(ps: just making an observation -- I know nothing of electronics so I'm oblivious to the finer details of building these devices...)

(pps: I'd be interested in getting the MP3 OnDemand PS product but it's too expensive, I'd rather go with an inverter and deal with the noise...)