Need phone solution

I am looking for a solution for my offline endeavors. I am a teenager and I live with my parents and of course we have a phone. I have a cellphone for myself but it has no service on it. I tried Nextiva today but I could not find the correct software for my phone's operating system (windows phone8.) Is there a solution besides Google voice that will give me a professional sounding line or would it be more personable to just get service on my phone and use my personal phone instead? I don't want my parents or siblings picking so the lines need to be seperate

Grasshopper.com

Skype personal number

callfire.com, you can get a line for $1 per month + $0.05 per minute