Im trying to find a Gunsmoke Episode: Matt Dillon is chasing a man that stole some money with two other men, the man was traded or given an Indian woman,she was traded to him by an Indian chief who felt she was bad luck. The Indian woman, the man she belong to , and Matt Dillon were eventually held up in a shack running from the other two men looking for their share of the money. Matt Dillon, The Indian woman and the man she now belong to ran out of water and the Indian woman convinced Matt Dillon and the man she now belong to, to trade the money to the men for some water so they could survive, once they traded the water for the money Matt Dillon let the man and the Indian woman go (The Indian woman was smart and she helped the man she was traded to do the right thing) and Matt went after the men with the money.

Google "gunsmoke episodes" (without quote marks). There are several sites, including imdb, that list the titles and summaries from 1955-1975.

It might be The Squaw, Jan. 6, 1975, Season 20, episode 14.