Best and worse ways to spend money to get better

What are your thoughts on the best and worse ways to spend money to improve? The best free ways? And the mediocre ways?

What sort of improvement do you see?

My thoughts:

Best free:
1) YouTube videos. Especially those by St Louis Chess Club. You’ll see lots of improvement if you are a beginner. Try watching one a day.
2) Puzzle rush on chess.com. But only a little improvement seen so far. I do daily as it is easy to do and fun :D.

Worst $: Books. I saw little improvement from them once I got the basics down. I still waste about $50 a year on them in hopes of finding a good one. The only book I recommend is The Chessmaster Checklist by Andrew Soltis. So hundreds of dollars over the years for little benefit.

Best $: www.chesspractice.com. I see continuous improvement. After each game, I copy and paste the game’s PGN there for analysis. Multiple colored arrows show best/worse moves and their values. What if allows you to test alternative moves easy. I use about 10 hours a week. So cost per hour is 5 cents an hour. $20 a year.

Mediocre $: Chess coaches. The few times I tried a coach, all they did was repeat the obvious. About $20 to $100 PER HOUR. Expensive. If you go this way, expect to spend hundreds a year to get improvement. Maybe worth it for beginners.

Best Free:
I don't know. I haven't worked hard to improve in something like 10 years. Back then it was mostly puzzles you could do online for free. These days there's probably more stuff.

Best $:
Books. But like you said, you can waste money. Read reviews, ask around, then buy 1 or 2 high quality books, and don't get any more until you've thoroughly studied them. $50 for 100 hours of instruction is hard to beat.

Also very good is chessbase. What is it? $100-200? But it's easily 100s of hours of reference material. You can use it every time you play a game, or want to work on an opening, or want to research a player, or build a collection of attacks, or endgames. There are tools to run statistics on your own games, etc.

Mediocre:
Chess coaches. I suppose they're very useful when pairing a qualified coach with a young talented player, but pairing a random titled player with an adult hobbyist? Nah. You're an adult. You can figure out how to read books on your own.

Also mediocre IMO: pretty much anything online. It's not terrible, but it's not great either.

Worst:
Books (yes I know I put them as best too)
People who buy fad books, or pretty much any book an an opening know that this is a huge waste of time and money.

I assume there is a lot of ridiculous content online too, I just haven't looked around for it.

Many have differing experiences.

My BEST : a few outstanding books.  Agree that 80 % of chess books are poor, but I've learned the most from a few great ones.

GOOD : certain software. Recently I use Hiarcs most, together with the free Stockfish. Previously used Shredder & still fire it up at times.  Also good is playing in local clubs & tournaments.

MEDIOCRE : Fritz. About 12 years ago it was the first software I purchased. Too many bells & whistles and they didn't all work. They advised re-installing : no help. About three years ago I make the mistake of buying the latest version. Rarely use it. Couldn't get the engine to work on my laptop. Their support was worthless.

WORST : a chessbase DVD. Cost as much as an expensive book. Had trouble understanding, due both to the dialect & poor speakers on my laptop. Had to rewind again & again to follow. Finally got half through, miserable every minute. Haven't gotten it out since. Never again.  Feel the same about videos. The information density of a video is low. Most of us can comprehend written material twice as fast as the spoken word. A book is always by your side, can be taken with you and can be opened almost instantly without booting.