How long should I wait before getting a reply for an on campus job?

I have applied to two different jobs on my college campus. The first one is a laboratory research assistant. The second one is the assistant manager of a store. I applied to the first one two days ago and the second one I applied to today. How long can I realistically expect to wait before I hear a reply back from the employer?

Realistically there is no answer.

If you interviewed in person for the job, you should hear back in 1-2 weeks or whenever they told you. If you just applied online, you might never hear back unless they are interested.