What Exactly is your question? This sentence could be written more fluidly.
"When at the fair, not only can I eat tasty food, but I can also view awesome fireworks."
Or I would completely reorganize it like this.
"At the fair, I can eat really tasty food, and see cool fireworks displays."
Answer:
More jobs and money
Explanation:
Already did it and I got it right SO TRUST ME ;)
You would write it in the casual form. You wouldn't write it informal because it would sound too unprofessional. And making it formal, well, some people wouldn't understand if you were to write in the formal way. They wouldn't understand the words. So just the casual way would do.