American girl looking for 1 room flat (max €350)

I’m a 22 year old American girl with a dog (2 kg) looking for a small flat accessible easily by public transport from RUB. I’m quiet, clean, and easygoing. I currently only have mostly clothing items and my dog, but plan to purchase some small furniture in the next few months. My dog is usually quiet (he only barks if a loud noise startles him) and well behaved. I have friends in the area that I can leave him with if I’m gone for an extended amount of time. I speak some german and can always have friends translate for me if needed.