Im from centreville, va about 5 minutes from manassas. Theres tons of courses out there. A few around you are:

Fairfax National Golf course: 27 hole golf course. lots of trees, seldom water. rate:3.9/5
Bull Run Golf Course: 18 holes, heard its ok, never played there
General's Ridge: 18 holes, beautiful course, very hard. up and down and up and down. Plays on a mountain. great long course though. rate: 4.2/5
Forest greens: 18 holes, nice course overall. 4.2/5
Prince William Golf course: 18 holes, eh its ok... nice but not at the same time.3.5/5

If you live in manassas theres this great deal you can get. My family just joined for the 2nd year. its three golf courses in the prince william area. (Forest greens, prince william, and generals ridge) and you pay a one years fee just like joining a club and you get to play at all three courses. The prices seem pretty decent from what i saw. This way you dont get bored of just one course all the time. The anem is called Prince william County Park Authority golf: the number is 703-221-0123. I hope this helps you out some.

There is also something called VSGA. (Virginia State Golf Association). For about 60$ you get a card that lots of different courses in virginia. This card gives you free green fees, but you have to pay for cart. www.VSGA.org. This is good if you like to travel and play at different courses. The best thing is that they have The Homestead course. ranked #4 in the US for public course. With this card you can play for 26$ instead of $110.

If you have any other questions or need help just email me.