You can put in the zip code of the area you are visiting, but I'm pretty sure the pricing and plans are the same everywhere. The costs will depend on which plan you choose. Personally, I have the $60/month plan with unlimited calls and texts and 2MB of data, but you can choose based upon your needs. You can buy the plan at any AT&T store (at the top of the page, click on "Store Locations and Appoinments" to find a store close to where you'll be staying.)
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.