Animation software recommendation for masOS Sierra

We are looking to download a Animation program that is not to expensive, Mac and user friendly.

Any recommendation?

My daughter is into Animation. I would considered her in between a beginner and an amateur. We have a Mac mini with macOS Sierra 10.12.6 operating system and 8 GB of Memory, 2.3 GHz Intel Core i5 processor, HD Graphics 3000 512 MG. She also has a USB Wacom drawing pad that we need to interface with the program.