What pisses me off, is that with carriers, and devices, they are NOT consistent.
Example: T-mo $30/month 100min/Unlimited Text/Unlimited Voice. No tethering. BUT, you grab various Android devices, turn on tethering on the device, sometimes it works, sometimes it doesn't, depending on the device (and these are stock devices, still carrier locked). Go Figure?!?!?! Apple device, tethering errors out. Blackberry Device total crap shoot, sometimes it works, sometimes not. WP, nope, nada, tells you to buy tethering package.
Talking to other people with other carriers and devices, they run into the same thing. The one consistency I have noticed (but can't really confirm), is that you are more likely to get tethering, even if you don't pay for it, with an Android device. And if it was a "Flagship" device at the time it came out, without any hacking or rooting.