guitar string

I been searching clothing for my kids at the yard sale online here in the valley and while browsing I saw this guy selling his guitar but it needs a new string in it. I was wondering if you can buy a string here in the Valley? I never seen any music accessories store in the area but good thing we can search it online the best way possible to find the things we need. I look up online, I found this D'Addario at musician's friend  and I was surprised for the prices of their guitar strings! I thought it would be expensive and surprisingly the price is really good. This might be a good deal, just need a new string and it will be look like new. Nice gift for a friend who loves to play guitar.