I’ve heard from multiple people that it’s common to dumpster dive paper cups from fast food places, which can be refilled at the soda station.
While some of the people dumpster diving for drink cups from are unhoused, some of them do have money for a drink but would rather not give Coca Cola or Mc Donalds their money.
Would you go in the garbage to grab a cup for a pop? Would the fast food place the cup is from have any bearing on your decision? Would you stick your hand in the trash bin, or would you just take a cup that happened to be left on a table?