Summer Associate Intern

I was emailed that I had been selected to interview with the firm. I was asked what dates/times I was available for a phone interview. The perception from the email was very professional.
The phone interview was informal. I was asked to go over my background/resume. I was also asked how I would be able to pay for my living expenses during the internship since it wasn't paid. The interviewer then asked me how this position ranked in terms of desirability compared to other internship positions. The interviewer was very kind and answered all the questions I had of him at the end of the interview. The next week I received an email saying I had been offered the internship, and shortly thereafter I received a phone call from my interviewer letting me know. I had a few days to decide. I emailed them back, and accepted the offer.