ioffer.com is usually full of fakes as far as I know. The quality will be far inferior to that of an authentic bag, and it just may fall apart in a week.
Please think twice about buying a fake bag since often you are supporting an income for terrorist organizations among other unsavory groups you wouldn't want to support.
Fake Designer Handbags - LoveToKnow Handbags
You can google for several articles linking fake designer bags to terrorists.
There are lots of beautiful handbags that are not "designer" if designer bags are higher than your desired price point. Likewise, you could simply set aside $x every month for a year to save up for an authentic of the bag you really want.