After a month, I got my first salary inwages from this factory.

When we say "get a salary", we mean to receive it regularly, not just one time.
Here's another option:

After a month, I received my first salary payment from the factory.

(I don't see much need to say "this" factory, as it's the only one being discussed.)

HR of the factory charged me some fees for the dormitory and canteen and I forget the correct figures.

You could say "the factory HR charged me some fees" if you want to be explicit that you mean the HR belonging to the factory, but, that seems fairly obvious.

I bought a Rolex wrist watch which cost me nearly 200 yuan (about US$ 25 at the time) at a free market nearby.

I am not familiar with the phrase "free market" in this sense, so I am not sure what is meant.

The only use of "free market" that I know is to mean a freely competitive one--often in the phrase "free market economy".

We have the phrases "open air market" and "street market" which are usually informal markets, and often fairly unregulated or even temporary.

The watch looked magnificent shining in the sunlight,; I liked it.

I think we shouldn't use a comma in between two independent clauses, unless there is some sort of joining conjunction.

It is awkward sounding for the second clause to be in present after the first part was in the past.

I suggest that if you want to convey that you still like it now, you use some sort of transitional tense like this:

The watch looked magnificent shining in the sunlight, and I have found that I like it.

I didn't understand why rich people buy expensive ones at Specialty Store in downtown, because they hadve no difference in my eyes.

We need a conjunction to join the independent clauses.

Also, by saying "I didn't understand" you're implying that you may have changed your understanding since then.
If you still don't understand, then it would be more natural to write "I don't understand..." here.

I even saw a young female worker bargaineding with the boss and gave 150paying 150 yuan for an Omega watch.

Or "I even saw a young female worker who bargained with the boss and gave 150 yuan (or whatever unit) for an Omega watch.

You can use "gave", but we probably more often use "pay" here.

The boss complained that he would lose money if he acceptsed the price,; however, I guess that she probably would gegot the deal when I went awayafter I left.

"After I went away" is not wrong, but I think "after I left" is simpler and so sounds better.

I fixed some verb tense issues.

I told my mother's friend's daughter that I wanted to find a job at a company in downtown.

Or "at a company in the downtown area"

She agreed with me because she knew the place was not for me.

Yours isn't wrong, but you could also say, for example, "she agreed with my decision"

In fact, I saw her picture in my hometown.

I don't understand who "her" is here.

Her mother had introduced her as a candidate to be my girlfriend about a year ago, although I didn't know ithat.

If I knoew the story, I might have feelt embarrassment and probably would not gohave gone to her house.

Fixing verb tenses

Though she was beautiful, with attractive eyes and long hair.

I secretly thanked my mother because she was not the kind I would love.

If you actually said "thanks" to your mother, then you should say "I thanked my mother".

But if you only thank her in your mind, but haven't told her, then the way you wrote it was exactly right.

I told her, "I am going to downtown tomorrow,; I hope your boyfriend (the supervisor) resignholds the job for me if I don't come back."

I am guessing what you mean; I don't understand how you wrote it.

Normally a person resigns a job when they tell the company they are quitting or retiring, meaning they stop working at the job.

You're welcome at any time,; we'll do the rest for you!"

Sshe replied readily.

If this is the end of the previous sentence, then "she" should not be capitalized.

What would be waiting for me in downtown,? I didn't sleep well that night.

After a month, I got paid my first salary inat this factory.

HR of tThe factory HR charged me some fees for the dormitory and canteen andbut I forget the correct figures.

I bought a Rolex wrist watch which cost me nearly 200 yuan (about US$ 25 at the time) at a free market nearby.

The watch looked magnificent shining in the sunlight, so I liked it.

I didn't understand why rich people buyought expensive ones at Sspecialty Sstore ins downtown, because they hadwere no differencet in my eyes.

I even saw a young female worker bargained with the boss and gavestore owner to pay 150 for an Omega watch.

The bossstore owner complained that he would lose money if he acceptsed the price, however, I guess that she probably would gegot the deal when I went away.

I didn't like working inat the factory.

I told my mother's friend's daughter that I wanted to find a job at a company in downtown.

In the US, "downtown" is used without an article.

Her mother had introduced her to beas my girlfriend about a year ago although I didn't know it.

If I knoew the story, I might feel embarrassmented and probably would not go to her house though she was beautiful with attractive eyes and long hair.

This is subjective tense since you're hypothesizing.

Though she was beautiful with attractive eyes and long hair.

Incomplete sentence

I secretly thank my mother because she was not the kind of person I would love.

I told her, "I am going to downtown tomorrow,. I hope your boyfriend (the supervisor) resignterminates the job for me if I don't come back."

You're welcome at any time, w. We'll do the rest for you!"

What would be waiting for me in downtown, I didn't kept me from sleeping well that night.

HR of the factory charged me some fees for the dormitory and canteen, and I forget the correexact figures.

I bought a knockoff Rolex wrist watch which cost me nearly 200 yuan (about US$ 25 at the time) at a free market nearby.

I think that adding "knockoff" here makes the low price that comes later make more sense!

The watch looked magnificent shining in the sunlight,; I liked it.

I didn't understand why rich people buy expensive ones at Sthe specialty Sstore ins downtown, because they had no difference in my eyes.

I even saw a young female worker who bargained with the boss and gaveoffered only 150 for an Omega watch.

The boss complained that he would lose money if he acceptsed the price,; however, I guess that she probably would gegot the deal when I went awayafter I left.

I told my mother's friend's daughter that I wanted to find a job at a company in downtown.

Her mother had introduced her to bme myas a potential girlfriend about a year ago, although I didn't know itrecognize it at the time.

My mother didn't tell me theat story.

If I know the storyhad known, I might feelhave felt embarrassmented and probably would not gohave gone to her house.

ThoughHowever, she was beautiful, with attractive eyes and long hair.

I secretly thanked my mother because she was not the kind of person I would love.

I told her, "I am going to downtown tomorrow,. I hope your boyfriend (the supervisor) resigns the job for me if I don't come back."

I don't know what you mean by "resigns the job".

You're welcome at any time,; we'll do the rest for you!" she replied readily

She replied readily.

What would be waiting for me in downtown,? I didn't sleep well that night.