A Reno charter school threatened with forced closure because of its financial problems has found a way to stay open and cut costs by $200,000 a year. The news comes as a relief to staff and students of Rainshadow Community Charter High School. Earlier this year, teachers of the small, privately run school agreed to forgo their salaries for two months so the campus could finish the academic year. Money problems result from the price of rent at the school’s location, 121 Vesta Street. The school pays $17,000 a month for the Midtown building, which comes to a little more than $200,000 a year, according to Principal Toby Wiedenmayer. Rent has been a quarter of the school’s expenses, which is more than it can afford with 113 students.