What is the correct way to say it?
- It's not a big deal to me.
- It's not a big deal for me.
Also, should I use "it's not" or "it's no"?
Either is acceptable. I would probably choose "for me", personally, but I would not think it strange to hear someone speak either form.
As for your second question, I would say that "It's no big deal for me" carries more emphasis on 'no' than "It's not a big deal for me." Both are equally acceptable, and the difference is very subtle (in fact, some people may disagree with me on that difference in the first place).
Also, you can use "not" or "no", but if you use "no", you need to omit the article, "a".
It's not a big deal. It's no big deal.
All the variations you list are correct. Stylistically, I would go with either:
It's not a big deal to me.
It's no big deal for me.
The meaning is just barely different between these: the "for me" construction carries more of a 'volunteering for a task' implication than the "to me" version. So "The choice of stuffing for this year's turkey is really not a big deal to me", but "Cooking Thanksgiving dinner is no big deal for me."
"To me" to me (lol) seems to express opinion, whereas, "for me" is talking more about how something affects you.
Examples: To me, it's too hot in here. (In my opinion, it needs to be cooler in here. A cooler temperature would better suite this place/situation.) It's too hot for me. (It's hotter than what I can handle.)