$30. Pay online and there aren't any taxes (yet), and there aren't additional fees because it's prepaid. Additional minutes are 10c and last for 3 months+ depending on how many you buy.

It does not include tethering. I'm trying to find a way around it simply on principle, but you can add it for $15/month. (edit: others mention it seems to be based on user-agent sniffing, this backs up what I've seen so far)

I'm very happy with it so far. Much cheaper, and a bit better customer service overall than I had with Verizon.