Questions and ASIC Usb miners from china

[usbskoot]

New to the forums and i have questions

The usb miners out there need about 0.5A correct? How can they run 20+ on one computer when outlets (atleast in sweden) are capped at 10A.
I know a factory that can clone for example USB erupter and sell them to me at 5 dollars each. Will it be worth it? What kind of equipment will i need?

If i want a nice, costeffective ASIC miner, what should i buy? i have about 250 euros to invest.