“I guess I’ve created something that everyone really needs,” said Nannini, a Grand Blanc, Mich., teacher who just started her fourth year in the classroom.

Jump has made a lot of her money selling science curriculum for the early grades, helping her colleagues teach 7-year-olds about scientific discovery. She has split her earnings between her family, charity and her school, including buying one classroom a smart board.

Stephen Wakefield, spokesman for ASCD, a prominent teacher training organization that has a blog promoting ways for teachers to get help online, said no national organizations approve or rate the multitude of online curricula available to teachers. However many offer lists of places for teachers to explore, he said.

Kathy Smith, a Seattle parent with two daughters in public school, says she knows teachers get materials from a variety of sources and she trusts them to make good decisions about what they choose to share with their students.

“I’ve got a lot of faith in teachers,” she said. “I don’t see any problem using computer sites for supplementation at all.”

Becky Smith, a special education teacher from rural Alabama, says everything she has gotten off teacherspayteachers.com has been free. Smith says the website saves her driving time and cash, because she can buy only what she needs — not a $20 workbook filled with a variety of things.

She also likes the idea of supporting other teachers, not corporations.

“I was on there for hours just looking for things before school started,” she said.