You fill your reusable grocery bags with all the bottle caps you can carry & bring them home.
They end up sitting in your parents attic (obviously you werent able to keep them in your shoebox of an apartment), collecting dust, until one day a nuclear bomb drops. Everyone you care about dies.
Fortunately, bottle caps have become the new main currency!
Congratulations!!! You're rich!
Who needs loved ones when you have cold hard bottlecaps.
The End!