The expression is used to preface a tentative statement of one's opinion. By deprecating the opinion to follow—suggesting its value is only two cents, a very small amount—the user of the phrase, showing politeness and humility, hopes to lessen the impact of a possibly contentious statement.

Is it my two sense or cents?

It should be "my two cents", which is a very, very common phrase in American English. Quite common in British English, too. Alternative is "my two pence worth".

How do you use two cents worth in a sentence?

Your two cents' worth is your opinion about something, even if nobody has asked you for it. Your father kept telling me to hush up but you know me, I had to put in my two cents' worth.