Cataati
The Cataati were once a proud and accomplished race numbering in millions of their kind. But then the Borg found them, and they, as well as thousands of other races, were assimilated. In all, only around 30 Cataati starships containing a few thousand people in total escaped the assimilation.
As most of the escaping ships were lacking in basic supplies, the survivors were constantly undernourished and prone to debilitating decease. Perhaps most damaging was the loss of the ability to replicate materials. Cataati technology is dependent upon thorium isotopes as the power source, and sadly enough during the assimilation by the Borg, the survivors lost the ability to replicate the isotopes. This lead to they being doomed to wander the stars, scavenging or begging for thorium wherever it could be found.
However, although the Cataati suffered greatly they did not lose their ability to be hard nosed traders. Indeed, they also once held the Federation starship U.S.S. Voyager to ransom. This, of course, because they had the right bargaining chip.