1. Where can we buy fast food like hotdogs?

- We can buy fast food like hotdogs on almost every street corner in the USA.

2. What kind of food can we find on the street?
- We can find drinks, hotdogs and pretzels.

3. How much is fast food like hotdogs and pretzels?
- A hot dog is 1,000 won and a pretzel is 500 won.

(Are the answers all grammatical? Would you correct some errors?)

In questions 1 and 3, I'd do a bit of correcting:

How much is fast food, such as hotdogs and pretzels?

How would you correct question 1?

In question 2, I wouldn't want to find any food on the street!! Here's how I'd revise this:
What kind of food can we find [or get or buy] from street vendors?

1. Where can we buy fast food like hotdogs?

- We can buy fast food like hotdogs at various places, including food stalls, food trucks, and fast food restaurants, which are commonly found on almost every street corner in the USA.

2. What kind of food can we find on the street?
- On the street, we can find a variety of food options, such as drinks, hotdogs, and pretzels.

3. How much is fast food like hotdogs and pretzels?
- The prices may vary depending on the location and the establishment, but on average, a hot dog typically costs 1,000 won and a pretzel costs around 500 won.

As an AI language model, I strive to provide grammatically accurate responses. I have made some minor modifications to improve the grammar and clarity of the responses you provided.