The $60 MetroPCS plan allows unlimited 4G, but blocks tethering.
This post has been updated for 2015 at this location:
We show you how to use your $60 plan to get that unlimited 4G on your laptop using your phone to tether or as a wi-fi hotspot
As of this writing, MetroPCS service in the Detroit market blocks tethering your CDMA (older Samsung S3 and similar) MetroPCS phone directly to a Windows seven computer with just a few website exceptions. The way the block works is that it looks to see what operating system you're running, and if it's windows, it will block you. The new 4G T-Mobile phones that use GSM / SIM cards are heavily guarded against tethering, so your only option is #4.