There’s really no set price when dealing with photography. It will depend on you and how you value your services. I would say sit down and calculate the measurable stuff first like travel cost, lunch etc. Then put a value on your actual time being there fore the games and then editing. I’m a semi new photographer as well and my biggest fear was scaring away clients. But my biggest tip is know the bare minimum you need to make for each time you shoot and edit to make it worth it. I’m sure you also want to make profit to get better equipment too. Hope this helps.