> This is a chance to become a full time employee, the first, with equity and a say in the business.

That's different. Equity is a form of payment (although, admittedly, it is a gamble). However, the way that you advertised it here really makes it sound like you are looking for free work, and a naieve student to take advantage of. And working without any sort of compensation is indeed being taken advantage of.

Also, as a side note, I suspect (and Google seems to support) that American students have far higher costs for going to university -- I believe that in Europe, the tuition fees are significantly cheaper thanks to government subsidies. With lower costs, there's less pressure to earn money to cover the costs.