Since electricity cost is not an issue, overclocked S1s will run at 200GH/s.
You can probably pick up 3 S1s and a PSU for ~$500.
Since my son is getting ready to go back to school, I'm sending along 6 S1s that he is going to run for me. We are splitting the BTC those miners earn 50/50.
Electricity is not an issue in the sense that he does not have to pay for it. He can't suck down 15KW with the dorm infrastructure. The S1s will put out about 800W of heat which is a lot more than S3s. He can't just wish for the heat to leave the room, he would have to run the AC and hope the roommate doesn't get mad.
An S3 would be a better option in a small dorm. In a large warehouse or garage an S1 would be reasonable.