sdrealtor is right that lowball offers are generally not productive. To me, the best way to get a deal is to window shop (so you know the products) and not buy until there’s a discount sale. It’s like not buying any consumer goods throughout the whole year and buying only during the Black Friday sale.
The key is to control the itch to buy and buy only when the deal is too good to pass-up. If everyone did that, sellers would have to adjust their pricing drastically downward. I don’t recommend this strategy to everyone because it would kill the economy.