Destin Bell, the founder of fitness app Card.io, secured $150,000 in start-up funds after persistently emailing the CEO of Niantic.Niantic initially rejected Bell's pitch, but he emailed the CEO weekly for three months until they agreed to invest.Bell appeared on Shark Tank to seek additional funds and received an offer of $150,000 for a 15% equity stake in his company.With the encouragement of his mother, Bell accepted the deal and continues to grow the Card.io app.