You could probably get one of the MH knockoff dolls at any dollar store and practice on that first. There is a bit of a learning curve when it comes to customizing dolls. Also, for just starting out, I would recommend Apple Barrel acrylic paints. You can find them at any JoAnn or Michaels stores and they are roughly $1-2 each.
They key to is to not get frustrated and give up. We all have to start somewhere. :)