A Kentwood mother of three has organized a free formal attire clothing drive, collecting more than 350 dresses, suits, jewelry, shoes and more to help local high school students look their best for homecoming without the hefty price tag.Shannon Sample said she understands firsthand how quickly homecoming costs can add up."We know that times are rough right now. The economy is very pricey. So with homecoming, the dresses and the guy suits can be …