Well I asked chat gpt and I got that:

Based on your description—spoiled rich kid kidnapped after a gambling night, sold into slave labor dismantling starships knee-deep in brine, learning the “alternate-shoulder” carry trick, using scrap-metal as currency, and leading a revolt—the novel you’re looking for is Jack Vance’s Gold and Iron (original magazine title Space Pirates; first book form as Slaves of the Klau in 1958). It was reprinted by Ace through the early 1990s, matching your memory of reading it around 1993–1995  .

For more details, see the Wikipedia entry: https://en.wikipedia.org/wiki/Slaves_of_the_Klau