I am very confused by these aircards, I've read from some people that they only cost $50-$60 and you're good to go. But I see data plans for another $60 a month, plus other aircards that cost over $150. Is it false that you can get one for just $60 and that's it? Or am I going to have to pay a monthly fee? Can I just grab one on eBay for 20 bucks without a data plan?