When you purchase teaching resources with your own user on TeachersPayTeachers.com you aqcuire a personal license. With that comes the use of the resource in your own classroom, year after year. Even if you change schools, the resource belongs to you. Not bad! 🙂 Some teachers are reimbursed by their schools, other schools have purchasing accounts.
You may also offer your colleagues to purchase licenses through you, giving them a -50% discount. For a fair split, a lot of teachers add the cost for both the original license and the extra at half off, and pay half each. The drawback is that the download is only available through your account. If your colleague wants to have the download on their own TpT account, they must purchase their own license.
You may not share the resource with others without an extra license per person. You may not send it to anyone, post it online (including school/district servers). This is the equivalent of stealing, and none of us would do that offline either. Just as anyone else that create, artists and designers for instance, I rely on you and others to support my work. I am beyond grateful for all of you that do the right thing, and pay for the correct amount of licenses. I know you are one of them, so I thank you!