Sometimes selling your startup for $3m today beats making $500k a year for the next six years. You get the money upfront. You can invest it. Start something new. Take some time off. And probably the biggest thing... someone else takes the risk from here. Because that $500k isn't guaranteed for the next six years. There's something pretty damn nice about turning years of future profits into cash in your bank account today. Especially if you've already been building the thing for…