how much will cost macbook with 64gb RAM

Impossible to say.

That depends on what specific MacBook you want and where you are in the world and what other configurations you make to it. Storage, Screen size, CPU etc....

You can check the Apple Store and configure a MacBook as you want it and you will get a price for it.

click here ➜ Buy Mac - Apple

Be a little less helpless… 🤨

Visit the online Apple site for your country and click the Buy button for a MacBook. Configure it with 64 GB and the cost will be in your local currency for that specific device configuration. Otherwise, impossible for us to quote a cost.