Still you would need to know a bit more. Somebody getting more than just the lens could manage to get additional discounts. If you only want to have the lens you wouldn't get the same price. Some shops offer e-quotes, valid for 7 days. Usually that's the best offer you can get if it's just for the lens.
The reason why Rashkae pointed to price is guide is also that certain shops (not listed here, of course) offer the lens quite cheap initially but try to sell you filters and other stuffs on top. Needless to say that the filter is actually cheap and crappy but the price somewhere at rooftop, to make up for the discount given for the lens.