Gas Dryer runs, ignites, but no heat

I just bought a new home and my father in law gave me a older Frigidaire gas dryer and it runs great but no heat. I checked the gas line and it has good air flow. When I turn it on, it starts spinning and I can see the igniter burning but no flame. I hate to have to buy a new right now so if anyone can give me any advise I would be very greatful. Thank you.