Tap on the the 'Make Offer' button to negotiate and agree to a fair price for an item. (Keep in mind, the 'Make Offer' button will only be visible if the seller has indicated they're negotiable on the price of their listed item.) Follow the prompts to enter your offer amount and submit your offer. Once an offer is accepted, you will be directed to the Buy Item page.
Please note, by making an offer on an item, you understand that you're committed to buy the item if your offer is accepted by the seller.