What are some alternatives?
When comparing Sampulator and Ableton, you can also consider the following products
Splice Beat Maker - Make and share beats in your browser
NanoStudio - NanoStudio is a recording studio for iOS, OS X and Windows.
BlokDust - Join blocks together to build sounds with this web-based music making app.
AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
Ramsophone - A generative art/music machine. (Be sure to refresh!)
Keezy Drummer - Make a beat in seconds