I've never shopped at the site, but I did check it out and the prices seem quite high. IMHO, it should never cost more than $100 for a knockoff.
Also, never buy a Coach knockoff - they are reasonably priced bags and if you have a Coach Outlet within 50 miles of your home you definitely go there for some great deals.
I have purchased a couple of LV knockoffs, and a couple Dior knockoffs. I either buy them in person or see if I can spot a good deal on ebay. Of course they always claim they are "authentic" but I know better.