Strange sounds in my house?

Ok, so me and my friend were in the bathroom doing our make up, she saw a bug and ran away, by the time i looked at the bug she came back and we heard a big bang from the attic opening in her bathroom, we ran to her room. i ran out to get camera batteries in the living room, using a cell phone as a flashlight, and i turned around and all i saw was a figure of someone or something standing right behind me. i grabbed the batteries and ran. my friend has had recent experiences in the house, when she first moved in she saw a figure of a little girl, she said it was transparent but she could see it, wearing a dress and had long hair and about 3 years old (estimate), other experiences she has had are she could hear people talking when no one was here, hearing footsteps and she has seen a re-occuring black cat running around the house, in the bathroom, in her room, and in the living room. she has also seen something sit on her bed, the imprint was visable. could we be dealing with the paranormal? how would we be able to find out for sure, nothing that costs money (i.e. ghost hunters, paranormal equiptment such as infered thermometers)