Sell study guides built from public video courses

There are some remarkable free courses on YouTube — forty-hour playlists that teach a whole subject properly. Almost nobody finishes one. The reason is not the teaching, it is that there are no notes, no index, no practice questions and no way to revise except scrubbing back through forty hours of video.

That gap is a product. A well-made study guide for a course thousands of people are working through sells steadily for years and costs about twenty cents of input to produce. The constraint is not technical and not commercial — it is that the lecturer’s words are theirs, and the entire business depends on understanding exactly where that line sits.

What you are actually selling

Structure, and the ability to revise without the video. The course is free and stays free; you are not selling access to it. You are selling the artefact that makes it finishable: a chapter map, a summary of each section in your words, worked examples, a glossary, and forty practice questions with answers.

Think of it as the textbook that the course never had. The buyer already has the lectures and is not paying you for them. They are paying because week three is where people quit, and having the material in a form you can read on a train changes whether they get to week four.

The second use is better for most people. Give the guide away in exchange for an email, and it becomes the top of a funnel for a paid cohort, a consulting practice or your own course. The guide costs the same either way and the free version reaches ten times as many people.

The numbers

Input cost is negligible. This is a product where the time is the whole investment and the return depends entirely on picking a course people are actually working through.

The break-even line is the one that matters, and it is why this is a portfolio rather than a single product. Eighty-seven copies is a low bar for a course with a large audience and an unreachable one for a course with two thousand total views. Most of the risk is in the choice of course, not in the making.

Five guides across five courses in the same field is the shape that works. They share a template, they cross-sell to each other, and one of the five will outsell the other four combined.

How it works

1. Choose a course with evidence of an audience, and check it first. View counts in the hundreds of thousands across the playlist, comments from people saying they are partway through, and ideally an existing paid course in the same subject — proof someone pays to learn this.
2. Pull the whole playlist in order. Playlist order is the course structure and it is worth keeping; a guide whose chapters do not match the video numbering is annoying in a way that shows up in refunds.
3. Map the course before writing anything. Section per video, topics per section, dependencies between them. This map is the single most valuable page in the finished guide and takes an afternoon.
4. Write summaries in your own words, working from the transcript. Read the section, close it, write the summary. This is the step that makes the product yours, and it is not optional for reasons covered below.
5. Build the worked examples yourself. Take the concept the lecturer taught and construct a different example. Reproducing the lecturer’s example is copying; teaching the same concept with your own is authorship, and it is also more useful, because the reader has already seen theirs.
6. Write practice questions with answers, forty or so. This is what buyers say they value most and what almost no free resource provides.
7. Add a glossary and a cross-reference index. Term, one-line definition, and the section it appears in. Cheap to build from your own summaries and the thing readers use most after week one.
8. Ship as PDF and EPUB, sold from a single page. Gumroad or similar. Do not build a platform for this.

Link every section of the guide to the video timestamp it covers. It sends readers back to the free course, which is both the right relationship with the material and what makes the guide feel like a companion rather than a substitute.

Where it gets hard

Choosing the wrong course wastes the entire twenty-five hours. There is no salvage. Spend a day on the choice — read the comments on the course, look for people asking whether notes exist, check whether anyone already sells one. Someone already selling one is a good sign, not a bad one.

Writing a study guide is genuinely hard work. Twenty-five hours is the honest figure and a fifth of it is drafting; the rest is judgement about what to include. A guide assembled by feeding transcripts to a model and formatting the output is obviously that, refunds at a high rate, and burns the store account you were going to sell the next four from.

Discovery is the real problem. The people who need this are inside the course, and you cannot advertise there. What works is being genuinely useful where they gather — answering questions about the course in the subreddit, publishing the chapter map free, giving the first two sections away.

The course can be taken down. Channels delete playlists and courses get reorganised. Your guide survives it — it is your writing — but the link between them breaks, so keep the video IDs and be prepared to reissue.

Limitations

The transcript is the lecturer’s words and remains theirs. A transcript of someone’s course is a copy of their lecture in another format. Selling it, or selling a lightly-edited version of it, is republishing their work without a licence, and a paraphrase close enough to track the original sentence by sentence is not meaningfully different. Use the transcript the way you would use a lecture you attended and took notes on: as the source you learn from and then write from.

What you can sell is your own summary, your own structure, your own examples and your own questions. The practical test is whether the guide would still make sense to someone who had never seen the course. If it only works as a substitute for watching, it is a substitute for watching, and that is the thing you may not sell.

Quote sparingly, briefly, and with attribution — a definition or a memorable line, credited to the lecturer and the video, is ordinary scholarly practice. Chapters of transcribed speech are not.

Attribute the course prominently and link to it. Do not use the lecturer’s name or the course title in a way that implies they endorse or authored the guide, and do not use their branding. “An independent study guide for [course], by [you]” is accurate and is the wording to use.

Automatic captions get technical terms and proper nouns wrong, which in a course is exactly the vocabulary that matters. Check every term against how it appears on screen or in the course’s own materials before it goes into your glossary.

Some courses have no captions at all, in which case there is nothing to extract and no tool changes that.

FAQ

Do I need the lecturer’s permission?

Not to watch a public course and write your own notes about it, which is what this is. You would need permission to reproduce their material, which is what the Limitations section exists to keep you away from. Telling the lecturer what you have made is worth doing anyway — a good number will link to it, which solves your distribution problem in a single email.

Can a language model write it for me?

It can draft summaries and question sets from a section, and using it that way saves real hours. It cannot make the judgement calls — what to cut, where learners get stuck, which example teaches the idea — and a guide where nobody made those calls reads exactly like one. Draft with it, then rewrite.

What price actually works?

$19 to $49 for a substantial guide to a course people are serious about. Below $19 the buyer assumes it is thin; above $49 they compare it to a paid course rather than to a textbook. Free in exchange for an email is a different and often better business.

Is it better to sell the guide or give it away?

Give it away if you have anything else to sell — a cohort, consulting, your own course — because the reach is an order of magnitude greater and the guide proves you can teach. Sell it if the guide is the whole product.

How do I know a course has enough of an audience?

Look for people in the comments describing where they are in the course, ask in the subject’s forums whether anyone has notes, and check whether a paid alternative exists. A course with a large view count but no evidence of anyone working through it is people watching the first video, and those people do not buy study guides.