I usually go after games not with the mindset of 'would I pay $60 for this?' but 'would I pay $60 for this today?' Sometimes I'll see a game I'm interested in, but not hyped for- let's use Enslaved: Journey to the West as an example. The Journey to the West connection intrigued me, but I wasn't immediately drawn in by the gameplay footage. So I forgot about it. Years later, I'm browsing around Gamestop for something new and come across a $3 dollar copy of Enslaved. That one I bought, and I loved it. It's not so much that it dropped to some magical dollar amount that suddenly made it desirable, but more the timing of finding it- I was looking for something new that day, and I just happened across this last-gen game I was already curious about. It could have just as easily been the $5 copy of Heavenly Sword I bought on a similar day last year. (obviously, when I say 'new' I mean 'new to me'.)
I do notice though, that for the most part, I'm a lot more deliberate about games over $20 or $30. Basically, the higher price points are the games I decide I want at release, and it simply becomes a matter of when I actually get around to buying them that determines how much I pay. The lower prices are the ones I consider when I go in just to browse, to see if anything catches my eye that day. So I guess it's less buying specific games at specific prices, and more having a range I'm comfortable impulse buying in.