Before you go back-to-school shopping, read this

Daniel Blas | USA TODAY Collegiate Correspondent

July is back-to-school month, according to Experian Marketing Services, the start of one of the largest consumer-spending events of the year — second only to winter holiday shopping. It is also the month in which retailers sent 41% of their back-to-school outreach e-mails in 2012.

Before hitting delete — or, as companies prefer, accessing their online marketplaces — there are some things college students must know before spending money. Students from K-12 and college this season will spend a combined $84 billion, as the National Retail Federation estimates.

The peak of back-to-school shopping season occurs in late July/early August, according to Experian research, and retailers continue to evolve their strategies to boost sales. Promotions this year began as early as June, and advertisements increasingly target parents, especially those who use social media.

Here are three things to know before you buy:

1. Different people pay different prices for the same product

Online stores try to "price discriminate," charging each customer the maximum he or she is willing to pay, says Ryan Hudson, founder of Honey, a free Google Chrome add-on that automatically searches for Internet discount codes at checkout .

Honey, a consumer advocate of sorts with 350,000 users, sees $10 million of shopping activity a month and is committed to getting cheapest prices for customers. One trick to combat price discrimination is cart abandonment, the practice of not purchasing an item after adding it to an online shopping cart. Retailers frequently send cart abandoners coupons the next day to incentivize purchases.

2. There are ways to game the system

While retailers are becoming savvier, customers should use the Internet — which has "complete price transparency," according to Hudson — to their advantage. He suggests websites such as Slickdeals and FatWallet, which aggregate promotions and provide expert knowledge about discounts. Some marketplaces such as Amazon offer price-comparison charts and have buying guides to help "our customers find the right school supplies at great prices," according to an Amazon spokeswoman.

The spokeswoman wrote in an e-mail that the Amazon Student feature — free for college students for a six-month period, and then $39 a year after that — offers exclusive deals, such as $5 store credit for friends referred to the Student program, and free two-day shipping on items in Amazon's inventory filled with hundreds of millions of components.

3. Textbooks can be cheap

Instead of shelling out $250 for a rarely used textbook, students have alternatives when buying. A plethora of websites have sprouted up — AbeBooks, Chegg and eBooks, to mention a few — that sell previously owned books as an attempt to tackle the issue of high cost.

One such site, Book.ly, serves as a price-comparison platform across all websites.

As of publication, it claimed to have saved users more than $11 million. Ohio State University leads all colleges with $255,000 saved since Book.ly was founded in 2009 by Brandeis University graduate Igor Pedan.

Sites such as Amazon offer up to 70% of the value for students looking to sell used print textbooks . Whether purchasing textbooks, clothing or electronics, buying a gift card — which often costs 80 cents to the dollar — is a way to save money on high-ticket items.

Daniel Blas is a summer 2013 Collegiate Correspondent.