Pricing in WD

I need a bit of help with picking a good HDD

I've got a 120GB SSD for now, and I want to buy a 1-2TB HDD

I'm looking at them with a 100$ budget but I'd like to get out with less so I can get my parents a decent keyboard for the old PC.

Any suggestions?

I was looking at WD greens, and they all looked like a good bargain. But I also noticed that there are 2 very similar 1TB and 2TB drives but what is the difference (other than item code)?

Links to the drives?

It might be the cache size that makes them different.

For performance reasons I would stay away from the greens. Low RPMs and park the heads often to conserve power. WD Black are going to be the better option or even a blue, but do yourself a favor and steer clear of the greens.

$88 US and they have a promo code that will take $10 off.