If you mean buying a hardware keyboard with dvorak letters, then don't. If you learn to touch type (and there's no point switching to Dvorak if you don't intend to) then you don't need to look at your keyboard, indeed being able to will only teach you bad habits.

Print a paper copy of the key layout to pin next to your monitor when starting out and use a typing tutor like gtypist to train yourself instead.

I didn't by a physical keyboard as such, any operating system allows you to change the layout and I just did that.

You can print the layout out on a piece of paper until you have learned them but if you plan on looking at the keyboard when you type you are not going to benefit from a dvorak keyboard.

If you do deciede to learn it, just know that it is totally worth it - your hands will thank you.

I wrote the Dvorak letters on my keyboard with a marker and by the time it wore off each key I knew what that key was. It took a couple of weeks.