One thing that might be used as a money sink would be the neccesity to repair equipment due to wear after usage.
Many games got it in one way or the other. Diablo comes to mind. Unique items should not wear down as they are pretty hard to come by. neither should specific boss loot. At least not wear down to the level were it cannot be repaired.
Fixers and special repair shops should be the source of repairing of worn down equipment. Shops should repair the item back to its original state, but it should cost a lot depending on ql of the item. While Fixers might fumble and only repair it partially. Maybe even the wear value of the item will be reduced, meaning that the item will break down faster.
Unless an item get fixed it will become broken and unusable until repaired. In some cases even become unrepairable.
As stated uniques, implants, utility equipment should be excempt fromm this. And probably some boss loot that is hard to come by. But weapons, armor, vehicles, tool kits and so on should be affected.