I understand that many people collect on particular stuffthings because they love ithem so much.

I have a strong love for books too, but I do not want to make a whole collection of my favorite novels and comics.

For me, it seems like a waste of money, as I can pay a much lower price for the digital form.

My childhood friend bought the whole series of all his favorite comics, and dedicate a room to storeing them.

I’m currently working now, so I do not study any subjects at the moment.

I’m currently working now, so I do not study any subjects at the moment.

The first reason is that I have a knack for learning English, so I decided to pursue a career that could make use of ithat skill.

Another reason is that at that time me and, my parents and I believed that the business sector offered better salaries than other sectors.

While the courses that required English skills were rather easy for me, those that required Mmath skills, such as financial analysis, were torture for me, as I am very bad at Mmath.

I wish I had chosen to study an English linguistics major instead.

I understand that many people collect on particular stuffthings because they love ithem so much.

"stuff" is ok but "things" sounds better with an adjective before

For me, it seems like a waste of money, as I can pay a much lower price for the digital form.

I am not sure because I do not know a lot of people, but there are manymany of the people that I do know who are into collecting.

It was ok, but this is more natural

My childhood friend bought the whole series of all his favorite comics, and dedicated a room to store them.

"whole series of his favorite comic" is better to show that it was the whole series of ONE comic (that is, one title)

4. Do a lot of people in Vietnam collect things, and if so, what do they collect?

Since the first part is a yes/no question, you have to add "and if so" before continuing with another question that assumes a yes response to the first ("and if not" if it assumes a no response to the first)

I’m currently working now, so I doam not studying any subject at the moment.

"at the moment" typically triggers the use of present continuous tense

I’m currently working now, so I doam not studying any subject at the moment.

"currently" + "now" is redundant

Another reason is that, at thate time me and, my parents and I believed that the business sector offered better salaries than others.

It's not strictly followed, but in formal writing, the convention is to always put yourself after the "and" in the subject, i.e. "my parents and I" (and use the subject pronoun "I"). The way you wrote it is how you will often hear it spoken, however, so you're not exactly wrong.

While the courses that required English skills were rather easy for me, those that required Mmath skills, such as financial analysis, were torture for me, as I am very bad at Mmath.

Typically I don't see "math" capitalized. I believe you can technically capitalize it when it refers to a specific class in school (and not just the general concept of math), but I get the impression this is falling out of favor in English. Of course, "English" would always be capitalized, whether referring to a class or not, since it's the name of a language.

I wish I had chosen to studytake the English linguistics major instead.

1. Is it very interesting?