Summer may be in full swing, but that doesn't mean you have to let your brain off the hook. With the expansion of technology comes a plethora of invaluable resources to stretch your mind and gain valuable skills--and what better time to do so than while tanning? Here are a few ways to try something new this summer, each a few thousand dollars cheaper than summer school tuition.

1. Improve your language skills.

With increased globalization comes the increased demand for language skills. Knowing more than one language proves extremely valuable in the professional world while expanding your personal capabilities for communication. Free to download at the App Store, Duolingo provides free language lessons in Spanish, French, German, Italian, Portuguese, Dutch, Irish, Danish, Swedish, Esperanto, Turkish, Norwegian and Ukrainian through a series of fun, interactive lessons that devote time to vocabulary, speaking and reading and writing comprehension.

2. Expand your economic knowledge.

You may remember them from their bestselling book Freakonomics and the four sequels that followed--Stephen Dubner and sometimes-guest Steve Levitt created a weekly podcast available for download through both mobile apps and online. Entitled Freakonomics Radio, the podcast was launched five years ago and continues weekly to this day. The episodes are interesting, engaging and thought-provoking while remaining accessible by Dubner's introduction to all topics covered. The podcasts introduce new ways to think about everyday phenomena ranging from sleeping patterns to the country's rate of incarceration to online dating to terrorism.

3. Get technical.

The science and technology fields are booming, and understanding basic web and app coding is and will continue to be a lucrative, applicable tool. Coding can seem daunting to tackle, what with its extremely nuanced nature and jargon. But Code Academy overcomes that, offering online step-by-step interactive coding lessons, allowing you to watch your progress come alive as you simulate creating different aspects and features of webpages.

4. Make the most of your commute.

Albeit via car, foot or subway, many of us who work during the summer are burdened by some sort of commute. This can often feel like a waste of time usually spent listening to music or aimlessly checking various social media accounts. Moreover, we often vow to read more books over the summer only to find that buying and then lugging a book to and from our destinations is heavy on both our wallets and our shoulders. Audiobooks, available both on iTunes and via providers such as Audible, bypass these obstacles, providing an often-free but altogether cheaper way to fill that wasted commute time with some summer reading.

5. Explore universities' online courses.

In theory, summer courses through your university provide you with the opportunity to explore fields out of sheer interest without pushing you behind schedule to graduate. However in practice, said online courses often create nearly as many problems as they solve, coming with hefty price tags and massive time commitments. Cue free online courses: although they don't provide college credit, they allow you to explore a field at no cost, neither monetary nor timing. An organization called Academic Earth boasts a database of over 750 online courses and 8,500 online lectures, all free of charge, open to the public and provided by internationally-renowned universities such as Yale, Stanford and Oxford.

Wherever your interests may lie, don't let them die; take advantage of the incredible tools we have today to use your newfound free time to learn on your own terms.