I'm currently using a mouse to animate stick figure and its frustrating to draw it out
also what the px for the perfect stickfigure?

1.) Keep animating with your mouse, you'll get used to it
2.) There is no such thing as a perfect stickfigure
3.) To get better at mouse, I suggest you keep doodling in your free time, holding your pen and resting your wrist like you're holding a mouse.

I suggest to practice line tool when at mouse but if you prefer at brush,go kill your unpatient attitude and continue animating because patient is very needed when animating.
Also it depends at your style what px size you want :D

There is no 'perfect' stickfigure, nor is there an easy way to animate. My advice is to keep practising - some of the best stickfigure animators here are mouse users.

Interesting fact: Camila (head mod for this section and leader of Clan Nemesis) began her animating career using brush and mouse.

Just keep practicing.

If you're not good with the brush+mouse, go ahead and use the line tool. I don't have a tablet either, and using the line tool is by far the best option you have right now. Of course, that implies a lot more patience, as Hitsu said, but it will definitely pay off in the end. Just take your time.

2 out of the three years I've been animating I worked with mouse. Is just practice man, just be patient and don't give up.

I find it's easier to make a straight line when not drunk. Haha!
It's also easier to use the line tool to make a straight line than with the brush tool. But like many things in life, practice makes perfect.

i've been using a mouse for 8 years LOL

You could use the line tool instead. It actually helped me in my stickfigure construction now. Or if you really prefer Brush, Be patient and work hard...don't also have a shakey hand when you're focusing on drawing it like me >.>