I guess I'm just not very tech savvy because I'm not really following any of these recommendations. Is there not something that I can buy that connects via USB or something to my current macbook pro that I can make copies of all of my important files to so that I don't lose them if this machine crashes? That's really all I'm looking for - to back up my music and school documents.
Maybe you should educate yourself on how those things work if you want to save a bit of money.
If you are not tech savvy at all and have no interest in being tech savvy, you can buy any ready-made external hard drives and enclosure by a number of manufacturers such as seagate, western digital, lacie, etc.
It's the easiest thing to do, and also usually the most expensive.
If all you do is backup important files, any external drive will do really.
If you want to save some money, you can buy an external drive enclosure, and buy a hard drive that fits inside it and install it into the enclosure yourself(it's really easy, even a caveman could do it). That could save you a bit of money.
One thing to consider is the speed you want your external hard drive to run at.(which is probably where the geek gibberish lost you). If all you do is backup some files once in a while, and have no intention whatsoever of "working" with your external hard drive, USB 2.0 is just fine and will suit your needs perfectly. It is the cheapest type of enclosure available as well. If you use your external as a scratch disk for photo/video editing and such, then, perhaps a FW800 (aka IEEE 1394b) enclosure would probably suit the bill better as the data transfer speed will be much, much faster.
If you intend to use Time Machine, you have to have a hard drive that is at least as big as the internal hard drive in your computer to be able to properly back everything up with room to spare.