How do I show proceeds from broker and barter exchange transaction in 'sales' section of 1099b?

You should have an entry in Box 13 on your 1099-B.

A secondary use of Form 1099-B is to report barter exchange transactions. A barter exchange is a network of people or companies who agree to trade property or services with one another without accepting payment in currency.

Barter exchanges use Box 13 of the form to report the fair market value of all goods and services received by an individual member of the exchange over the course of a year. In general, value received through a barter exchange is considered income and may be taxable.

As Champ Hal_Al replied to a similar post: "Do not enter at the 1099-B screen (investments).  Where you enter it, depends on why you received it. For example, if you have a sole proprietorship, you would enter it as "other income" (as opposed to gross receipts) on schedule C."

See original post here.