Analyse it ---
The lens can be bought for $430.00 delivered.
Without seeing the bag, strap, cleaning kit and UV filter but having a rough guess at the combined value of all items I would say that they would be worth about $50.00 total.
That figure would represent a very good profit margin for the dealer.
Price the items individually and see what you can come up with ----
Don't jump straight into deals like your example, you can save a lot of money by doing more research.