where give me link?

check chessbase.com

The Week In Chess website is one place.

Go to the download section.  Also, look for their archive section, to download many older pgn files that are no longer listed on the main page.

Another site is the University of Pittsburgh's Chess Page.

If only there were previous topics on this subject, so that one might search for it instead of starting a new one . . . ah, well, someday, yes?

Check here: http://www.pgnmentor.com/files.html

A ton of games, separated by opening, player, or tournament.  It takes some time to get them all (there's no option to download them all at once), but there are tons.

With programs like the Firefox add-on DownThemAll, you can download all of these pgn files from the pgnmentor site at the same time, automatically, while you're drinking your coffee or something. 

Then, when you have all of the pgn files in one folder, use the old DOS COPY command to combine them into one file, if that's desired.  For example:

     COPY *.pgn bigfile.pgn

will copy all of the pgn files in one folder to a single file, called bigfile.pgn.

So, Sahista, there ya go.  With minimal effort, you can "get a lot of chess games in one file."