I've had some experience in blender, but i'm not quite sure exactly what your asking for. but if your using blender for paper toys, i would stick to low-poly modeling rather than smoother higher poly models. the best way i've found for doing low poly modelling in blender is explained through these tutorials here:

http://www.youtube.com/user/PXstriker

and when you say "convert it to flat style" I'm not sure whether you mean simplifying your smooth models, or unfolding it into a flat pattern/template. if you mean unfolding so you can use it for building your paper toy template, use the program pepeakura designer found here:

http://www.tamasoft.co.jp/pepakura-en/

the program's worth every penny if you plan on making toys from 3d models.
if you need any help with anything, feel free to ask me. good luck :D

Thanks alot :) I was unaware of the low poly modelling options.
Also, in blender it is possible to unfold the models with UV rendering and seams. I have now learned that, i just need a way to export the files so i can print them, then add the tabs later. I will check out designer, but it seemed a bit pricey for me, even though i could easily model in 3d and take it into that, it just seems a little pricey. I'll fill you in if i find anything worth using that doesnt cost.

If you look up blender 'uv modeling' there should be some stuff on it, i just found a tutorial. Its relatively easy, you mark the cuts on it, and it unfolds from there with the uv window.