So, stay in your current job, set aside the 25% of your income you'd be losing by going to this startup, build up your savings, and find a company willing to hi

So, stay in your current job, set aside the 25% of your income you'd be losing by going to this startup, build up your savings, and find a company willing to hire you at or above your current salary. Don't subsidize a startup by taking a pay cut, and especially don't do it by digging into your savings, unless you're going to be one of the founders and get a larger equity grant to begin with.