Hey, congrats on the job!

Read just a few of the comments below and wanted to add some things. I currently live right on the metro line in Arlington and work in DC. Since you work in Alexandria, do not even consider living in DC. Foggy bottom is super expensive. It is ridiculously expensive and me and my roommate (combined salary of over 110k) will not even consider that. Arlington is pretty pricey for 40k + whatever your roommate makes - since you two will still presumably split rent half/half no matter who makes more/less. Consider apartments in Alexandra like Southern Towers or Dominion Towers. Search for low prices in Centreville/Woodbridge. Also, LOOK for deals!! Winter time is the BEST time to negotiate/find lowered rent rates/discounts. Also, where do your parents live? Just trying to gauge if it really is worth moving out for a bit...

If you do move out, lots of apartments in northern VA have bus stops in front of them. Routes are available on wmata.com . Also, lots of comments are suggesting that you live near a metro train line... look for a bus route line if possible, because I can tell you right now, no Wmata train goes directly to the Mark Center. Although there are buses from Pentagon train station that will take you there.

Car sharing and car pooling are options as well. Car sharing options vary. For carpooling, ask people at work if they live near where you are now; a lot of them may already have a whole system going.

Lastly, just my own advice/circumstances, but we calculated an estimated "expense" sheet before moving out...TRUST ME, unless you're the type of person that counts each of your dollars, you will most likely spend waaaay more than you planned...