This is my favorite and my very best find.  Most transfer tape was far too sticky for me (and somewhat expensive).  This isn't 12 inches wide, but I can cut more than one piece if I need bigger and I've been able to reuse it for a few pieces. 

This vinyl is perfect for classroom projects you want to be able to remove at the end of the school year such as desks, whiteboards, walls, and etc.  

This is the vinyl I use most often.  I have used it as a stencil and removed it from some projects--it is not as easy to remove as the other, but it can be done.  This is the vinyl you'll want for outdoor projects, signs, cars and etc. 

HTV requires a heat press of some type to make a tshirt, bag, or any other fabric project.  Personally, I have the Cricut Easy Press and I had zero issues. I used it for personal use and for our small business.

I bought this HTV multicolor pack a year or so ago and it has been perfect for having a variety of colors to add small details to projects. It has saved me from having to go out and purchase a whole roll for an accent color on multiple occastions.

Remember when using HTV you will want to mirror your project and put it on the mat shiny side down.