i've done it and see nothing wrong with asking.If the buyer has a price he wants to sell it now, let me know.If its more than i want to spend then I bid and hope for the best.If I like his "buy it now" price I will jump on it and end the bidding.I usually do it with an offer to pick up the item because sellers would rather have you pick up the item and avoid the shipping on a bike plus you get a chance to check it out.