In today's world of high-tech gadgets, Texas Instruments' relatively low-tech calculators stand out. Since the ‘90s, laptops have gotten faster and thinner, phones have become more powerful, and watches can pick up Wi-Fi—but the TI-83 graphing calculator, which was launched in 1996, essentially remains frozen in time. With a 6 MHz processor, no rechargable battery, and a screen like an old Game Boy, the TI-83 is far from impressive.

One would think that such outdated technology would eventually become affordable, but the price of a TI-83 or its successor, the cumbersome and only slightly upgraded TI-84 (launched in 2004), cost roughly the same as they did 10 years ago. A TI-83 will set a student back around $100, while the TI-84 still costs more than $100. Most obsolete gadgets lower in price (consider this $10 flip-phone), but the humble graphing calculator continues to boast a hefty price tag. What gives?

It's all about supply and demand.

Graphing calculators are still widely used by students, and schools have strict boundaries for what these gadgets can do. Many curriculums in American math classes require the use of a TI-83 or TI-84 graphing calculator (or its equivalent). The reliable calculators have been part of the classroom for so long, it’s hard to shake them. As Mic reports, many lesson plans revolve around just learning how to work the things—Pearson textbooks feature illustrations of Texas Instruments graphing calculators to help students better understand how to use the devices.

Public school education is notoriously slow to change methods, but even forward-thinking classrooms struggle to escape the grasp of the graphing calculator. Standardized tests like the SAT and ACT have strict rules about what devices students are allowed to use. When trapped within these small confines, teachers have no choice but to teach using the outmoded technology.

According to the College Board, here is a list of graphing calculators allowed into an SAT testing room:

Laptops, phones, and devices that connect to the Internet are obviously prohibited to prevent cheating. While other companies make slightly cheaper approved calculators, most students are pointed towards the TI-83 or TI-84; it's a lot easier to teach with one device instead of many.

When students have no choice but to purchase a calculator from a finite list of options, the sellers can feel free to set their price. According to The Washington Post, Texas Instruments took home 93 percent of U.S. graphing calculator sales between July 2013 and June 2014.

Barclays analyst Blayne Curtis told The Washington Postthat, "[c]ompared to other electronics this day and age there is very little content [in a TI-84 Plus]... Plastic case, small black and white screen, two semiconductor chips. The batteries are even not rechargeable like a cell phone." Curtis estimated that each calculator costs about $15-20 to make. Due to the high market price caused by high demand, he guesses that the company can boast a profit margin of over 50 percent.

As Mic reports, Texas Instruments maintains their monopoly with services like 1-800-TI-CARES and workshops that teach teachers how to use the devices. By cultivating their product as the norm in classrooms, the company is able to keep its stronghold in the market. Smartphones have successfully managed to edge out other gadgets like watches and cameras, but they have no place in a testing environment. For the time being, it looks like students and parents will continue to cough up big bucks for these clunky old calculators.