I bought a pedometer on the Auction site on-line, so I can measure my steps. If I walk for 10,000 steps a day, it will be helpful for my health. This product was made in China, and it is 1,500 won. It is inexpensive. Because I can check how many steps I can walk, it will be useful to take care of my health.

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Would you check my composition and let me know what expressions are in correct? Thank you.

In the second and the fifth sentences, the words "it" don't seem to refer to any particular noun; that is, the antecedent is not clear. Those sentences need rephrasing -- perhaps like this:

Walking 10,000 steps a day will be helpful for my health.

How can you rephrase the fifth sentence so there is no vague "it"?

In addition, I'd do something different with "It is inexpensive." That sentence seems to chop up the paragraph. Try rephrasing and attaching it to the sentence before it.

Let us know what you come up with.

=)

I bought a pedometer on the Auction site on-line, so I can measure my steps. If I walk for 10,000 steps a day, walking with the pedometer on my belt will be helpful for my health. This product was made in China, and it is 1,500 won. The pedometer is rather inexpensive. Because I can check how many steps I can walk, the item will be useful to take care of my health.

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Thank you. I corrected some expressions, would you check them,please?

Yes, it's better. How about this, though, for the last sentence:

Because I can check how many steps I walk each day, the pedometer will be useful as I take care of my health.

"... useful to take care of ..." is not standard phrasing.

=)

Your composition is generally well-written, but there are a few grammatical errors and awkward phrasings that can be corrected. Here's an edited version of your composition:

"I bought a pedometer online from an auction site so that I can measure my steps. Walking 10,000 steps a day can be beneficial for my health. This product was made in China and costs 1,500 won, making it affordable. Being able to track the number of steps I take is useful for maintaining my overall well-being."

Explanation:
- You mentioned buying the pedometer "on the Auction site on-line." It would be clearer to say "online from an auction site."
- The phrase "If I walk for 10,000 steps a day" can be changed to "Walking 10,000 steps a day" to make it more concise.
- "It will be helpful for my health" can be changed to "can be beneficial for my health" to convey the same message in a clearer way.
- Instead of saying "it is inexpensive," you can mention that the pedometer costs a specific amount, which is 1,500 won in this case.
- "Useful to take care of my health" can be changed to "useful for maintaining my overall well-being" to express the same idea in a more natural way.

I hope this helps!