There are several variants of the Baofeng UV-5_. All are pretty much the same. What you want is a model with current firmware. Amazon is a good source.
Personally, having owned a Baofeng for a year or so, I would spend the extra money for a basic "name brand" HT such as Yaesu, etc. They are not that much more, and aren't "disposables" with no factory or retailer support like a Baofeng.
After all, if you are going to go to the trouble of studying for the Ham exam and want a transceiver that will work when you need it most, isn't it worth it to buy a quality radio?