The people that go through the trouble of installing apks from random websites to not pay $1 are in the minority. What's more, most of them wouldn't pay that dollar if they couldn't find the cracked apk. So the only thing you're realistically doing is cutting yourself off of a huge market. Convenience sells, the Play Store does that
$1 - most probably. What about $20?
Unless your target market is a small niche of hackers, then yeah the vast majority would pay $20.
Just look at how many pay for music and video streaming services, when it's trivial to download anything for free from illicit sources.