How much is a Rolls-Royce Merlin engine worth?

I'm curious to know, just how much would one expect to pay for a Rolls-Royce Merlin engine? It's a historic piece of aviation technology, so I'm sure there's a premium placed on its rarity and significance. But, as someone who isn't overly familiar with the market for vintage aircraft parts, I'm at a loss as to what kind of price tag one might find attached to such a prestigious engine. Could you enlighten me on the potential value of a Rolls-Royce Merlin engine, and perhaps offer some insight into what factors might influence its worth?