1994. $5 could buy you enough at a fast-food joint to be full, and the quality at the time wasn't yet absolute garbage so people still did regularly eat fast-food hamburgers.
The fancy milkshake cost as much as one could expect to pay for an entire meal. To put this into context, you'd need a higher-end (not McDonald's anymore, think Five Guys or Shake Shack) fast-food restaurant, and how much you would pay for an entire satisfying meal there.
Maybe $25.
That's how expensive this milkshake was, at the time. The current-year equivalent of twenty-five-dollars. It was outrageously overpriced.
RT: https://poa.st/objects/614f383d-2f4f-46d0-b2f3-85e55eff9df6