really small arduino power supply

Zoomkat, fair enough and how many Watt rating is that?

5v * 1amp = 5watt power supply
vs
20-50W Max (so i'll reflect the min/max)
10-11v (after rectifier DC output and cap)

20W/11.5v = 1.73amps
50W/11.5 = 4.34 amps

20W/(11.5v > Regulator > 7V) (Recommended regulator voltage , which drops it down to 3/5v for the board) = 2.8amps
50W/(11.5v > Regulator > 5V) (not so good, as it stresses the regulator out) = 10 amps

?? 10 amps? am i doing this right..

20w/7v = 2.8?
50w/5v = 10amps.

sounds kinda right, but that's a lot of power for AU $2.19 (Free postage)