I prefer organic food, even if it is more expensive. Because I am very interested in health. There is an organic food brand called 'OLGA' in Korea. My mom and I often shop there and make and eat salad sandwich.

1. I'll let you know the result later. ✔

2. Would you like to pay in cash? ---> Are you paying in cash?

=> Your sentence has a correct grammatical structure, but this has the correct usage/ expression.

3. I'm going to try again. ---> I'll try again.

​=> Your sentence has a correct grammatical structure, but this has the correct usage/ expression.​