I buy most of my Coach bags from the outlet stores or the online sales. These bags are 100% authentic, you dont have to worry about knock offs. Prices are great too. I have seen people pay upwards of $80 for a bag that is clearly a fake. For $150 you can get an authentic bag that is of high quality.
Online sales happen often, but you need to recieve an email invite for it. You can go to http://coachfactory.com and click on BECOME A MEMBER to recieve the notification on their sales.