SEATTLE » Kristine Nannini spent her summer creating wall charts and student data sheets for her fifth grade class — and making $24,000 online by selling those same materials to other teachers.

Teachers like Nannini are making extra money providing materials to their cash-strapped and time-limited colleagues on curriculum sharing sites like teacherspayteachers.com, providing an alternative to more traditional — and generally more expensive — school supply stores. Many districts, teachers and parents say these sites are saving teachers time and money, and giving educators a quick way to make extra income.

There is a lot of money to potentially be made. Deanna Jump, a first-grade teacher at Central Fellowship Christian Academy in Macon, Ga., is teacherspayteachers.com’s top seller, earning about $1 million in sales over the past two years. She believes the site has been successful because educators are looking for new ways to engage their students, and the materials are relatively inexpensive and move beyond textbooks

“I want kids to be so excited about what they’re learning that they can’t wait to tell mom and dad,” she says.

Dozens of Internet forums have been created to help teachers distribute their material and pick up ideas from other educators. Teacherspayteachers.com is one of the biggest. It was started by a former teacher in New York in 2006 and quickly grew. Others followed, like the sharemylesson.com run by the American Federation of Teachers, the nation’s second largest teachers union, where free curriculum ideas and materials are offered.

While most characterize these sites as an inexpensive way for teachers to supplement textbook materials, some teachers may get pushback from administrators for their entrepreneurial efforts.

Seattle Public Schools’ recently revised its ethics policy, with the new policy prohibiting teachers from selling anything they developed on district time, said district spokeswoman Teresa Wippel.

“Anything created on their own time could also cross a gray line, depending on the item and how closely tied it is to classroom work,” she said.

Teacherspayteachers.com currently has about 300,000 items for sale plus more than 50,000 free items.

All told, more than 1 million teachers have bought or sold items on teacherspayteachers.com since it began. Teachers had $5 million in sales during August and September, said site founder Paul Edelman. After paying the site fees, teachers have collectively earned more than $14 million on the site since it was founded.

At all of the websites, the quality varies. Jump said she learned over the years that her colleagues — and their students — are only interested in professional-looking materials that offer the kind of information and instruction they need. Teachers are able to rate items offered for purchase or distribution.

Teachers often spend their own money on classroom supplies, despite receiving a few hundred dollars a year for that purpose from their districts. Increasingly, teachers say, they are going to these curriculum sharing sites to look for materials like the ones Nannini and Jump made available because their funds go further than at traditional school supply stores.

“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.