If you are enrolled in one of the many online schools available you're still going to be on a student budget and that may include the need for a roommate to help with expenses. One of the most important things about your new roommate is to ensure that they have a similar lifestyle to yours. If you're cramming for tests in the evening and having to get up early, you certainly don't want someone living with you that parties all night and keeps you awake.
The easiest way to avoid those types of problems is to room with another college student. Chances are that most, if not all, of your online classmates live in other areas, but why not check out your local college campus student board? You can easily find other students looking for a room or post your request for a roommate and chances are there are a lot of people looking. Living alone while attending an online school or a campus location can be far too pricey for some so sharing the expenses during the duration of your studies can really help out a lot.
Make sure that you are clear in your posting or when answering one about what your expectations are. Will you be sharing utility costs? What about groceries- will they be communal or each to their own? No matter how you slice it there will be a significant cost savings for both students, you just need to make sure they are perfectly clear on what "their share" means.
Another benefit to rooming with a fellow student is that it gives those of you in on line schools a bit more of that college experience. Your apartment building may not be a dorm, but sharing with another student who understands your schedule, pressures, and occasional need for a little celebration can enrich the experience as well as provide you both with a little support that only someone in your same circumstance can give.