I've been playing the guitar for about 8 years now without taking lessons, and it's very possible to do so, but if you do have the cash and time, i would suggest getting lessons.
If you're trying to learn by yourself, having a friend at the same level as you will help. When i first started, my friend would start doing riffs and every time i saw it i thought, "well if he's doing it, so can i!" You can find guitar tabs of songs you want to play and try to play them slowly (tabs are very easy to read). Also, i found Rocksmith as a pretty fun tool to learn songs and i can definitely see it being used to teach you proper techniques. Have fun!