@CashQu33n
Majority of the people I know on IMVU use ps/gimp for any 2d texturing and Blender or 3dmax for 3d modelling.
I would recommend you get familiar with ps for texturing as you can find any cracked/free version of it online for. Blender for 3d as it is a free software.
I never heard of procreate until you mentioned it. Just did a quick research about it and it looks like it is mostly a mobile app? I am guessing you may own a tablet of some sort. If that is the case and you are comfortable with it, go for it ! Practice yourself, learning IMVU texturing basics via Youtube.
I still would want for you to learn PS at some point as it is a great skill to learn beyond IMVU.
Just my sincere advice, good luck!