The thing with pricing is it is always and nothing more a matter of what someone will pay for it. You can always put any price you want on it and if someone pays that price, then you know. But it may have nothing to do with worth, but rather the desire of the buyer. And there is nothing particularly rare or unusual about the pictorial of animals and people on rugs. I have several myself. Sometimes the pictures of animals can refer to stories. Rugs with birds may refer to "The Conference of the Birds" by Farid ad-Din Attar. A lot of times animals are just that ... pretty designs. As far as reflecting the beliefs, in Iran, the religion of course is Islam. Often gazelles or deep type animals are used to depict the soul or the spirit, or sometimes just the manifestation of beauty. And sometimes animals may be used to reference stories from pre-Islamic or Zoroastrian times from ancient Persian history. But it's not rare or mysterious.