you can't make deals with someone where there is already bidders guys. come on. once someone bids that's it for you. if u can't top that bid there's no way u can make deals. if u know what an auction is then u know how this works.
There is an "advanced options" link near the bottom of the listing form on the left side. This will open up a menu of more options to use while listing an auction, including the minimum bid field.