Shops at an airport can be expensive because the airport will charge extortionate rents. It's a major source of profit for most large airports. They have a captive market with people who are waiting for flights, and they take full advantage of it. I can't comment on what the situation with camera stores there might be though.
I would suggest also looking in local camera shops. I bought mine in one a few years ago, and it was actually cheaper there than in one of the discount chains. The place that I bought mine also offered courses on basic photography, I didn't take advantage of that as I was too busy, but it may be worth thinking about if you don't know a lot about photography.
You will also need to buy some accessories for it, and unless you really know your cameras (or have a friend with you who does) you will need to ask someone at the shop as to what works with what. In that case, you will want to be sure you are dealing with to someone who knows what they are talking about, rather than just a minimum wage cash register minder.
I can't make any judgements as to your situation, but I wouldn't go off on a vacation with a camera that I've never used before. Get the camera well in advance of the trip and take it out and practice with it so you'll know how to use it. The last thing you want to be doing is sitting in your hotel room trying to figure how the hell the bloody thing works. Even worse is finding out that you ought to have some extra bit or bob, and you didn't get it and now you need to find a camera shop wherever you are. Plan on taking at least 500 photos under different conditions just to get familiar with how it works and what you can do with it. It's not like it's film these days, so it doesn't cost any money to practice with it. Also, upload the practice photos to your PC to take a good look at the results. The pictures can look different on a large screen than they do in the small one on the back of the camera and you will want to know if you are doing something wrong.
Don't forget things like camera bags (including one that hangs around your neck for walking around with), spare battery, a second (different) lens, lens covers, cleaning kit, extra memory cards, etc. I put UV filters over the lenses just to act as protectors. I also got a cheap tripod that will fold up small enough to fit in my suitcase, which I use occasionally so that I can get in group photos. I would also bring a cheap point and shoot camera for taking pub photos.
I'm not a photography nut by any means and I don't really know all that much about photography, but I do appreciate having some nice photos of friends and family and of vacations. My DSLR is a fairly low end Nikon but there's no comparison between it and any point and shoot camera that I've tried. Someone handed me his DSLR camera to take a photo of him with his wife, and the difference between that and my own point and shoot was so day and night that I went out and bought one of my own.