Forget about the rising costs of a good education. Have you checked that back-to-school supplies bill? According to the National Retail Federation (NRF), parents will shell out more than $40 billion for knapsacks, books, Sharpies, and sweater sets. That averages out to $483.28 for families with school-age children and twice that for those with college-bound kids.

The total spent on school-related stuff is more than Americans spent on vacations this summer and second only to the holiday season in terms of overall retail sales. A survey by found that the average shopper will spend $3,389 this year. That's just a few hundred dollars shy of the cost of tuition at a public four-year college.

Mom and Dad aren't total suckers, though. Some parents are making Junior foot part of the bill, kicking in an average of $84.58. It's never too early to ask the offspring to pick up the tab: Those six-to-12-year-olds opening their wallets for fall fare will kick in an average of $40.

What's a bust for family budgets is a boon to the retail trade. Perhaps you noticed that Todd Oldham dorm room chic replaced summer picnic supplies at your local Target (NYSE:TGT) and that extra-long twin sheets are now regular stock in store bedding departments. Woe is the college student who shows up at the dorm minus iPod and shiny new Dell (NASDAQ:DELL) computer.

According to the NRF, $7.5 billion will be spent on electronics, $8.8 billion on textbooks, $3.2 billion on clothing and accessories, $2.6 billion on dorm or apartment furnishings, $2.1 billion on school supplies, and $1.5 billion on shoes.

Since the 1990s, August and September have become very good months for product peddlers and their theme-starved window dressers. However, while this year retailers improved their back-to-school sales, their earnings report cards were less than glowing.

Moms and dads: Don't make school supply bills a four-year debt sentence. Plan ahead for next year's "must-haves," and consider investing in some of the stores running those back-to-school promotions. And get your kids involved in family finances at an early age. (They need all the help they can get.) Tell them any leftover savings from the school supplies budget can go toward their first tattoo or piercing.