Marketplace.tf bots and staff will never contact you over Steam or Discord. Any accounts asking you to buy, verify, check value, or deposit items is scamming you. Block the account and do not follow their orders.
I don't usually negotiate my prices on MP, but you can divide the $ price per 2 to get the one in keys. Then, please add me to trade the item you saw : https://steamcommunity.com/id/apothic-r/