Hello to everyone,
I just find this product (http://www.ebay.com/itm/1PCS-HLK-PM01-AC-DC-220V-to-5V-Step-Down-Power-Supply-Module-Household-Switch-/381475932950?hash=item58d1bccb16:g:J3cAAOSw7FRWVQuu) on eBay while looking for a power supply I can integrate in the next project.
What do you this, is it good to use for Arduino guided projects? It's reliable?
For what I can see, I can solder it on a breadboard where I will solder the 220V input too...
Thanks a lot (also for reading me)!
Well, unlike many things on eBay, this appears to be a reputable product corresponding to the manufacturer's page.
It is only 3 W - 600 mA, so if that is clearly sufficient, you are winning. 
I would be cautious mounting it on a breadboard (or designing a PCB) - you need plenty of space with no conductive "lands" between the mains side and anything else.
When posting eBay links to single items, remove the question mark and all following. Your proper link is http://www.ebay.com/itm/1PCS-HLK-PM01-AC-DC-220V-to-5V-Step-Down-Power-Supply-Module-Household-Switch-/381475932950
Paul__B:
I would be cautious mounting it on a breadboard (or designing a PCB) - you need plenty of space with no conductive "lands" between the mains side and anything else.
What do you mean exactly with "mains side"?
The connections that go to the power mains.