Please HELP!! (stupid dealership)

Ok so I go to the Dealership to tell them I got a Check Engine Light On, well he tells me it cost $89.00 just to look at my car and to tell me whats wrong with it. I will not pay $89 for someone to tell me its gonna cost more money to fix it. So i go to autozone and they give me the codes, P0455 Evaporative Emission Control System Leak Detected (gross leak) Large and P1448 Vent Control Valve. Does anyone know what those problems mean and how big and expensive is it to fix. SOMEONE PLEASE HELP.