Hello Blinx!
If you mean 2d animation (and not rigging) then I totally recommend you Clip Studio Paint EX. It is actually one of the most used softwares to animate in Japan. It works perfectly to animate sketches first and then "clean them up", adding lineart, color and so on.
BUT (there's always a but, right?) as in every animation software, there is quite a big learning curve.
Ah! Another good point is that is not that expensive! It costs around 60$ but they do sales quite often so you could get it cheaper. Unless you use an Ipad (like I do) because then you gotta pay a monthly subscription. It's a bummer, but it's worth it.
I hope it helps :)
C. Donut.