Secret arched doorway in room?

Okay so Ive always wanted to have a secret door in my room. And my parents will let me do it if I put the research and money in for it. Its going in my walk in cloest and will lead to the side of my house where the garden is. How much does it cost to carve a door, and I want it to be arched. Do they sell that at homedepot. As you can tell I know NOTHING help would be most appreciated, and ten points is the reward, lol THANKS =]