Being a good teacher requires more than just reading, writing and arithmetic these days -- cold hard cash has become a necessity to make the grade in U.S. classrooms.

Teachers spend an average of $589 of their own money on school supplies and instructional materials, according to a survey by The National School Supply and Equipment Association (search). For a profession that has an average salary of $44,684 that means making sacrifices and counting every penny.

Teresa Schirmer, a foreign language teacher at Saugerties High School in Saugerties, N.Y., said she puts $1,500 to $2,000 of her own money back into the classroom every year.

“We’re really on a string now,” said Schirmer who receives $100 for supplies from her school. “You have to order pens and pencils through your budget. You can basically buy nothing with that.”

But Schirmer's budget seems generous compared to what Ginny Beauchamp, an 8th grade U.S. History teacher at Nicholas Orem Middle School in Hyattsville, M.D., receives.

“We didn’t get a budget this year,” said Beauchamp, who's been a teacher for 28 years. “They gave me a bag of basic supplies -- chalk erasers, a sponge, paper clips, some markers and not too much else.”

Dorothy Porteus, a school support specialist with the New York Charter Schools Association (search) said the concept of "necessary supplies" means different things to different people.

“Everyone would like more in the classroom -- there’s no doubt about it, but you are given a budget because that’s what the tax payers can afford,” said Porteus. “The little add-ons are nice, but you have to make sure the necessities are there first.”

Porteus, who worked in public schools as a principal and teacher for 28 years, believes a school will always make sure teachers have instructional materials, but since supplies are a lower priority their budget may get cut.

To add ooh-la-la to her French classes, Schirmer spends money to make crepes for students, buy French films and CDs and educational games. But Schirmer said there are some things she can’t bring herself to pay for out of her own pocket -- like a heavy-duty stapler for her classroom that costs $59.99.

“It’s a supply the school should have on hand," she said.

And she pointed out that as students have become more tech-savvy, the necessary supplies have gotten pricier. “Before you could do workbook exercises, show some reel-to-reel movies, but you can’t teach them like that anymore," Schirmer said. "They are a different generation."

The government has tried to alleviate some of the checkbook crunching that teachers endure. The so-called "Crayola Credit (search)" which was signed into law by President Bush in March 2002, allows teachers to deduct up to $250 from their federal income taxes each year for out-of-pocket classroom expenses.  And there are efforts underway to expand the credit to at least $400 per year.

Beauchamp is prepared: “I have a stack of receipts already. Every bit helps.”

Porteus said over the years she has seen teachers find frugal ways to add items to their classroom -- such as shopping garage sales for games -- and even dish out cash to pay for students' lunch, clothes and field trips.

But Beauchamp said spending extra cash is part of the profession's unique responsibilities.

“I don’t like that it’s part of my job, but it is," said Beauchamp. "Teachers will make the decision in the end to get the things they need to do the job. I don’t have to have the nice posters I have in my room. I do it because I want a pleasant learning environment for my kids."