USB miners is like the dumbest decision you'll ever make... They profit you literally nothing, especially with the difficulty rising quickly.
So you buy a stick from sidehack or a reseller cost in the USA 30-40 dollars.
Just 1 your point it at this pool
https://bitcointalk.org/index.php?topic=1283990.0if we hit a block you get .24- .25 btc
if you are running a pc 24/7 the extra power is 5 watts about 4 kwatts a month about 50 kwatts a year.
at 12 cents a kwatt 6 dollars so for 1 year maybe 45 dollars and 2 years 51 dollars.
the chances are we will hit a block if we play for 2 years.
Exactly what Phil said.
This was the website I used to setup my usb miners.
The only thing you need is a USB hub that will deliver enough power per port, unless you have a hub that you are using half the ports.
Something like this might give you enough power, but is pricey.