I would definitely recommend trying to get on the inside of the startup somehow. A huge part of business is networking. Do anyone of your friends know someone who works at or owns a startup? See if they can put in a word for you and maybe get a face to face interview set up.
Make sure that you are clear that you are doing it for the educational experience and not for the money. I wouldn't necessarily offer to work for free, because I think that makes you sound a little desperate, but be clear that you aren't expecting to get paid a whole lot.
This is basically what I have done to get jobs the last two summers, and it has worked really well for me. Last summer, I worked for a guy who spoke in one of my comp sci classes and who I had a few connections with. The summer before that, I worked for an international nonprofit that I had several connections with. The pay was not great (basically just covered living expenses), but the experience was well worth it.
Make sure that you are clear that you are doing it for the educational experience and not for the money. I wouldn't necessarily offer to work for free, because I think that makes you sound a little desperate, but be clear that you aren't expecting to get paid a whole lot.
This is basically what I have done to get jobs the last two summers, and it has worked really well for me. Last summer, I worked for a guy who spoke in one of my comp sci classes and who I had a few connections with. The summer before that, I worked for an international nonprofit that I had several connections with. The pay was not great (basically just covered living expenses), but the experience was well worth it.