5$ USB Sound Card ( working out of box )

[demigod]

i badly need mic for skype. i wanna buy a usb sound card.

my question is mac is plug and play supported right.so if i buy a cheap usb sound card will it work
is there any possibility that it will work. any success ? i know it's hard to tell. But give me advice.
is there any chipset i have to check..?
or i have to choose only creative product...?

suggestion needed.

Thanks
demigod