There are a lot of cheap Android phones you can buy for around a $100 dollars. Most of them will be Chinese branded phones with horrible quality and with no service center. If your still open to getting a Blackberry, there are a few devices you can choose depending on your needs. Since Blackberry phones can easily install all the major app stores, you wont be missing any Android app on your device.
The Z10 was a flagship phone which is means built quality is really great. That was one factor that got me really interested with the Blackberry Z10 other than the super cheap $139 price tag.
The Blackberry Z3 is a budget phone that was supposed to compete with entry level devices. It never really took off since there was too much competition in this price level. But with the price drop of $99 this makes the phone a real bargain.
The Blackberry Q5 is something a lot of people looking for an Android capable phone with a full QWERTY keypad. The Q5 is probably the cheapest Android capable phone with a keypad at this price range. You get the best of both worlds with having the best keypad ever designed and a very high quality touch screen.