Check out http://visible.com (verizon) it's $40 per month for unlimited and you can use your phone as a hotspot.
I ditched Straight Talk over 2 months ago and went with Visible. I was using PDAnet to get around them not allowing data to be used as a hotspot and it was working fine. The issue I had was if you read the fine print if you exceed 60 GB usage they do a review of your account. If they somehow figured out you are using as a hot spot then you could get terminated.
You can actually get the service for as low as $25 per month.