It's a transformer, some diodes, a couple of capacitors and resistors and a voltage regulator, total cost of parts is about £20.
isolated outputs - means one transformer per output.
tl;dr - ripoff.
Disagree. I used to think the same, powered my PB with a good ole Boss PSU and a daisy chain, and really had some buzz, noises and weird interaction issues (even with a total current draw way below what the PSU could handle and nothing in the amp's loop). Then I bought a TC Nova Repeater, 24V 300mA, comes with it's own PSU, and the ground loops just ate my tone. Pulled the trigger for a Voodoolab ISO5, couldn't be happier - no more buzz, no more strange issues, clarity and dynamic were back... Oh and even more since I can now feed my booster and ODs with 18V, which greatly improve the dynamic. Finally sold the Nova Repeater (too complicated and too cold for me) but kept the Voodoolab, this thing changed my life.
@bandmaster188: you want something with isolated outputs - that's what prevents ground loops and other "interaction" issues - and preferably with toroidal transformers. There are quite a few isolated outputs PSUs so check the specs to find out which one fits your needs (power outlets count, current supply values, voltages, etc).
NB : You can still daisy chain 2 or more pedals on a same power outlet once you know which ones do work together and which ones don't, the main point is taht when 2 pedals don't get along fine (ie you get buzz, ticks, weird noises or even unexpected signal distortions when they are daisy chained that you don't have when testing each pedal in isolation), you have the option to feed them from distinct outlets, which is usually enough to solve the problem.
