I actually just got my first PODM this month and I love it! I was a little unsure of what they would be like, so often the stock photos just don't cut it, but it turned out great and I'm hoping to be able to get another one soon. The one I got is Aladdin and I found a scene that I liked for a decent price considering I couldn't be at the release to take advantage of the $24.95 park price. I paid $29 for mine, so just slightly over the original price. There's another scene that I'd love to get, but I've only seen that one for sale once before and it went for about $45, which is closer to the price of the PODM you're hoping for.
After I got this one, I did a little quick searching on the bay for more PODMs and I did see several movies with higher priced PODMs, like Snow White, as DisneyDyln mentioned, and Cinderella. So the $40 for your PODM sounds like it might be right in the ballpark, depending upon the movie. If you haven't already, take a look at the completed listings on the bay for your movie PODMs and see the price points where it actually sold and compare that with the scene you're hoping for. That might give you a better idea of price.
Hope that helps! Good luck!