Looking on the internet deeply has found these results:

no big deal is the most popular phrase on the web.

not a big deal 1656,000 results on the web	no big deal 125,300,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
TO A LIFE OF ONLYSEMI by cmacdaddy September 16, 2009. 17 24. 5. No big deal. It's not a big deal. No big deal but I'm pretty much a big deal. by mystery5232 September 06, 2011. LUXURY. Not A Big Deal. Christian Rock Hard s07e09 . The boys feel bad about downloading music for free. Watch Random Episode�... ... Spanish � Swedish � Thai � Turkish � Ukrainian � Vietnamese � Help translate! �\_ (?)_/�. There aren't any definitions for not a big deal yet. Can you define it? Feb 17, 2006 ... The mother : it's okay ! it's not a big deal. in another situation: a wife to her husband: do you prefer me to cook the dinner tonight or shall i ask�...	Seriously, it's no big deal. It's no big deal, Paul. All right! It's no big deal. Little cough, no big deal. Listen, this is no big deal. One seizure happens, maybe it's no big deal. See? Just stuck, no big deal. She's trying to convince herself it's no big deal.

not a big deal

1656,000 results on the web

no big deal

125,300,000 results on the web

More popular!

TO A LIFE OF ONLYSEMI
by cmacdaddy September 16, 2009. 17 24. 5. No big deal. It's not a big deal. No big deal but I'm pretty much a big deal. by mystery5232 September 06, 2011.
LUXURY. Not A Big Deal. Christian Rock Hard s07e09 . The boys feel bad about downloading music for free. Watch Random Episode�...
... Spanish � Swedish � Thai � Turkish � Ukrainian � Vietnamese � Help translate! �\_ (?)_/�. There aren't any definitions for not a big deal yet. Can you define it?
Feb 17, 2006 ... The mother : it's okay ! it's not a big deal. in another situation: a wife to her husband: do you prefer me to cook the dinner tonight or shall i ask�...