Honestly, I'd go with facebook. You can make a business or a group page (as I'm not entirely sure if it costs money to make a business page, but I've seen people get around it this way) on there, where you can display your photos for people to see examples of your work. You also have the added benefit of being able to communicate with people directly through this page, and you can spread the word through inviting people on your friends list. Inevitably facebook creeping will lead to your exposure, especially if the photos you display for examples are eye-catching. I've also seen photography businesses offer photoshoots to people for free or for a reduced rate in exchange for their publicity; find some gregarious classmates you know will spread the word, and offer to do this for them. make some simple business cards to have them give out. If their experience with you is good, they'll be likely to do this. Word of mouth can do wonders: though it may just start out with your friends, pretty soon your friends tell their friends who tell their moms who tell the people at their work, and so on and so forth. A friend of mine has a mom who built up a successful senior and family portrait business doing this. Best of luck to you!