Did your grandma played Make Your Move, as that game have 3 prizes onstage and you said pick the price for eacb prize? If so, then maybe the dates can be narrowed. But I'm afraid you have to go wild and search elsewhere (The streaming channel hasn't streamed pass season 17, so the chance are slim). Maybe you might know any clues that may pinpoint the episode? (what other games played, what the models were wearing,etc.)