Like Lazzer says, making human models (which requires alot more skill than to model something that's hard-surface and simple, like a key for an example), texturing it, rigging it and animating it takes quite some time and it's not something that will people will do for free as it requires alot more skill, knowledge and time than other typical services that you can find for free from people who like to help. I myself would have the skill to make a citizen model and animate it for you and it would take around 1-2 weeks but like I said, this type of work requires a reasonable payment unless you're super lucky and find someone who would do it for free. I have never seen anyone on the forums do this kind of work for someone for free. There were few members that shared a monster or two though that they have made for the community which I'm also planning to do in the end of summer, but that's pretty much all there's been.
I understand that you are young though and can't really pay but that's why I think you should look for someone who could re-texture the existing citizens for you as Lazzer said. It's alot more likely that you find someone who would do this if your project is intresting and good enough, and if you find someone really good at re-texturing, he/she could proably make a model look like it's a new and different model just by changing the texture.
Anyway, I hope you find someone who can help you with this matter and good luck with you project!