Witness a secret transaction

Witness a secret transaction is an unmarked quest in Fallout 2.

Detailed walkthrough
Talk to any of the four kids playing before the Wright Estate. Ask him what game they are playing and he will say they are imitating "metal people" that come from "metal insects" they have seen in the desert.

Bribe him with an unloaded pistol (the cheapest pistol you have will be taken) to show you where they saw them and follow him. You will find yourself hiding behind the boxes peeking at Salvatores trading with Enclave soldiers. Stay put until the transaction is over to receive the reward. Then leave without anyone noticing you.