Most brands are decent, and I don't know of any that are truly bad. I've used D'Addario, Fender, GHS, Ernie Ball, Elixir, etc. on my guitars and don't have anything bad to say about any of them. At this stage of your learning you really won't notice any differences (except string gauge!), so buy whatever strings are within your budget and easy to find, and change them often (at least every couple months or so). If you can buy over the internet, I've heard good things about
Webstrings - very inexpensive, and a lot of people who've bought them say they're good strings (I haven't tried them yet.)