asked a worker if it was in the wrong place. She said she'd take it up to the front and check. At the front, I had this conversation:

Cashier: "The clock was correctly marked."
Me: "Oh, so it was in the wrong place."
Cashier: "No, it's marked 75% off. I used a calculator to check."
Me: "So, if it was originally $100, it'd now be $25, right?"
Cashier: *hesitates* "Yes."
Me: "So, if it was originally $150, it'd now be about $37, right?"
Cashier: *blank look*
Me: "So, if it was originally $200, it'd now be $50, right?"
Cashier: *thinking*
Me: "But it's marked higher than $50."
Cashier: "Let me ask the manager."

They eventually sold me the clock for $32.99.