It's easy to assume that the more a gift costs -- especially where workplace gifts are concerned -- the more thoughtful it must be.

Of course, that's not true. Tell me you don't have at least a few holiday gifts tucked away in drawers and closets; even though you'll never use that monogrammed leather toiletry travel bag, it still doesn't feel right to throw it away. 

Fortunately, the true measure of thoughtfulness is that the gift makes a difference, however small, in the receiver's life.

And that means some of the best holiday gifts you can give -- especially to colleagues, co-workers, or friends -- can be free. (Giving gifts that cost nothing to your employees can be a little stickier; no matter how thoughtful, useful, and appropriate, some employees won't be able to see past the "free" factor.)

Here are a few free gifts that can make a genuine difference in another person's life. And if you don't feel comfortable giving something free, no problem: Just say, "I saw this and thought of you ..."

Adam Grant and I have a lot in common. Except that he has a PhD and is an extremely popular professor at a top-tier B school. And has written more best-selling books. And produces a great podcast. And consults with some of the most forward-thinking organizations in the world. And has a Rolodex to die for. 

Other than that, yep: We're a lot alike.

As Daniel Coyle says, Adam's Twitter feed delivers more good ideas per square inch than anything else on the web. 

If you know people looking for new ways to think about common problems, for fresh perspectives on leadership, for insights that will help improve their lives, send them a link to Adam's Twitter feed.

I promise they'll thank you.

2. A link to Duolingo, the language learning platform

Know someone who has talked a lot about -- but also struggled mightily with -- learning a language? 

Duolingo is a platform/app that gamifies the process of learning more than 30 languages. Users can also create clubs; think workout buddies to help you stay on track.

More people are learning a language on Duolingo than in U.S. public schools. And if that's not enough, my fluent-in-six-languages mother-in-law swears by it.

3. A link to the Synyster Gates School

Plenty of online courses and tutorials promise to make learning to play guitar easy. Don't believe the sales pitch: Learning to play an instrument -- any instrument -- takes time and effort and dedication. It's hard. 

But with the right teacher, it can be easier.

The Synyster Gates School was created by Avenged Sevenfold guitarist Synyster Gates (whom I interviewed) and his father, Brian Haner (Sr.), an accomplished guitarist and session player in his own right. The tutorial videos are outstanding. Papa Gates is clear, concise, and that rare blend of expert yet down to earth that sets great teachers apart. And he establishes a level of rapport that makes you want to learn. So does the community of guitarists on the site: They share tips, share their progress, and offer encouragement and praise.

And it's all free.

Send a link to a colleague who got frustrated and put her instrument away. Send a link to a friend who wants to learn but has never gotten started.

Sometimes the best gift you can give is a little nudge -- and a great resource.

Fitness and diet videos are one of the deepest rabbit holes you can fall into. It's hard to separate the wheat from all the chaff.

Athlean-X videos are all wheat and no chaff. While the intros can be a little long (sorry, Jeff C.), the tips, advice, and, most important, the science of fitness is spot-on. There's no sugarcoating. No shortcuts. No hacking your way to a better, healthier body.

Don't believe me? Try the Sore in 6 Minutes biceps workout.

If you know someone who spends a lot of time working out, give them a gift that helps them get maximum output for all that input.

5. A link to the Here's the Thing podcast

Sure, Alec Baldwin is a great actor, but he's also a great interviewer. 

Alec has a knack for delving past the who and what and into the why: the emotional journey we all go through as we try to achieve our own definitions of success.

Yep: There are tons of free online courses. I've tried a few.

Then a friend sent me a link to Mindware: Critical Thinking for the Information Age. Developed by Dr. Richard Nisbett, Mindware uses statistics, probability, and science -- in a fun way -- to help you overcome common biases. Like why it's highly unlikely that, if your first meal in a new restaurant is excellent, you will find the next meal to be as good. Or why economists regularly walk out of movies, and leave restaurant food uneaten. Or why it could be a mistake to use an office in a building you own as opposed to having your office in someone else's building. 

There are more than 2,000 courses on Coursera. And since we all know people who love to learn ...