If you’re looking to sell or rent your house, I would suggest Qimen Dunjia. It can help you find the right strategy, it might even be able to tell you why you’ve been unsuccessful so far. If there’s a problem with the property or with your approach to the transaction, Qimen Dunjia can let you know.
As for the best price – no, that is not something metaphysics can help you with. What’s the price that you can accept? That’s the best price.