As I've said before, I don't know whether to trust Origin
as people used to say it contained spyware/scanned your computer.
EA might have changed it by now (or not)
but I'll have to find out.

But if you don't care either way,
or you already willingly use Origin,
or if you just want to redeem it now and investigate later,
go to Origin's "On The House" page to add it to your Origin game library.

I don't know how long the offer will last,
could be a month, could be a day, no idea.
But once you redeem it, it's yours.

https://www.origin.com/gbr/en-us/store/free-games/on-the-house

WARNING: Mass Effect 2 contains swearing, blood/gore, violence, inappropriate themes, etc.
If you're too young, you may want to redeem it
for free and then check it out when you're older.  

I'm forced to use Origin because I have BF3 on PC,
(hopefully the NSA doesn't have my files by now, ....  )

I've heard of a way to bypass Origin but I'm not sure
if it's safe (from a "no virus" point of view)
or from a "has anyone ever been banned for bypassing Origin"
kinda way.
Well, I redeemed the game and when I actually have time
(free time? what is this dark magic? )
then I'll investigate that method and whether Origin still has spyware or not.
(Or if it ever did.)

It's nice we're getting all these free games.
Mass Effect 2 isn't even that old,
and it's been critically acclaimed too.

I would recommend playing Mass Effect 1 before playing Mass Effect 2, just because your choices from the first game transfer to the second game, and so on too. Plus it would help you learn some background stuff (although it is not required for the Mass Effect 2).

Also, from my experience, Origin is pretty safe (It is EA's game portal, after all). It's UI and system are pretty bad, but you can still play games on it, and that's all that really matters, right? 

They're also likely making Mass Effect 2 free because the newest game (Mass Effect Andromeda) comes out very soon (in March). AFAIK, the new game is standalone from the existing Mass Effect trilogy.

Thanks for the advice, Cody.
When I have spare time I'll probably give the game a try
and see if I like it enough to get the first game.
Yeah I think it was a clever and nice marketing idea
to give it for free to encourage greater sales of the newer game.

But regarding the privacy issue of Origin....
for years there's been talk online of Origin scanning
users' computers and using fairly private information
to help with advertisement purposes.
I guess to get to the bottom of this,
we'd have to inspect the EULA (End User License Agreement)
and also use software to determine what files are accessed
with Origin processes.
Some people have already done this on Reddit
but their conclusions didn't seem to be
that clear or I haven't read them properly yet.
And I can only find like 2 year old threads.

Hopefully you're right but I have my suspicions about Origin lol.
Origin bypass research here I come.
Although I wonder if you can just close Origin after starting
a game... (haven't played BF3 in ages so can't remember how Origin works lol.)