To get to Coron, Cebu Pacific flies 2x a day to Busuanga Airport. In Coron Municipality, Air Philippines also flies 2x a day, Zest Air flies once a day. Visit their websites for rates. Quite often they offer low, low promo rates. Monitor prices at their websites:

www.cebupacificair.com
www.airphilexpress.com
www.zestair.com.ph