Many "high-profile" entrepreneurial ventures seek [venture capital]? or [angel funding]? in order to get started. The first round of funding is usually at least $200,000 but first round funding of $25 million or more is not unheard of. In exchange for this money, investors receive equity? in the company. The founders of an entrepreneurial venture can expect to exchange as much as 50% of the company for the first round of investments.
An excellent resource for various topics in entrepreneurship is The Entpreneurial Edge at http://edge.lowe.org