Your Domain Market Pro powered domain marketplace allows for interested parties to either Buy Now domains or to make an offer for them.
Of course, including a price is optional, but if you include a price you give the buyer a guide to how much you want for the domain. If the price is right and the buyer likes it, then they can buy it right away. However, in any case, whether there is a price listed or not the buyer is able to place an offer for the domain.
There are two options how you can receive the offer. One is to have the prospective buyer register to the site and then the offer form is available when logged in (this will encourage sign-ups and build your list). Or, if you prefer to have the prospective buyer remain anonymous, the contact/offer form can be available right away and you can receive the offer via email.