Sure you can buy it in a store that sells software but you can get better deals on-line. But first of all decide what you want to do with the program. If it is just to make a few adjustments to your digital images the Photoshop Elements is more than adequate. Take a look at this website  http://www.graphic-design.com/Photoshop/vs_elements.html  and this will get you started and it can be purchased for $60 or so. If on the other hand you want to get heavily into graphic design as well as photography then you can pay  $400 to $600 for Photoshop CS4 depending on whether you are eligible for the student version or not.  This is a full suite of programs and can blow your mind! If you Google CS4 you will find dozens of websites both selling the programs and offering tutorials , hints and tips etc. You will see some dealers offering it for only a couple of hundred dollars but be aware that the low prices are for upgrades for folk that already own CS2 or CS3 and will be of no use to you. I hope this helps but feel free to ask more.