There ain't no such thing as a free lunch
ORIGIN & MEANING
"There ain't no such thing as a free lunch" (TANSTAAFL) is a popular adage communicating the idea that it is impossible to get something for nothing. Uses of the phrase dating back to the 1930s and 1940s have been found. The "free lunch" in the saying refers to the nineteenth-century practice in American bars of offering a "free lunch" in order to entice drinking customers.
The "free lunch" refers to the once-common tradition of saloons in the United States providing a "free" lunch to patrons who had purchased at least one drink. Many foods on offer were high in salt (e.g., ham, cheese, and salted crackers), so those who ate them ended up buying a lot of beer.
TANSTAAFL indicates an acknowledgement that in reality a person cannot get "something for nothing". Even if something appears to be free, there is always a cost to the person, although that may be a hidden cost or an externality.
HOW TANSTAAFL PERTAINS TO CONCRETE
Training: Perhaps you've seen these "N/C (no charge)" training events held by product distributors? They rope you in with the word "free" and attempt to teach about a subject they have little to no experience with while using products they sell (with an emphasis on selling products). Can you see the value in that?
Videos: These days the first place most people search for information is via a search engine, which typically shows results for videos. The problem with these videos is that the people making them don't know what they are talking about. It's the blind leading the blind, but if you're new to the industry you don't know who doesn't know what they claim to know.
Products: Drug dealers have been using this tactic for millennia. Offer a sample, get them hooked and you have a customer for life, albeit a short one. The same is true with concrete. Anyone remember UV sealers? Buy a gallon of UV sealer and get a free light, or vice versa. You start using it, it looks great at first but then starts delaminating. You start chasing your tail, grinding off and reapplying more and more UV sealer until the customers quit calling and you are out of money. Your concrete company had a short life, but for that small span of time the company selling you the UV sealer was banking off of you. It all started with that offer for a free gallon of sealer or light. TANSTAAFL.
Forums: The experts in any industry don't spend their valuable time on forums freely giving away their hard-earned knowledge. So that begs the question, who are the "experts" doling out advice? I'd be very wary of any free information gained from a forum.
I have always known this philosophy to be true. You get what you pay for, if you shop at Harbor Freight you know what you're getting or you will learn very quickly. Low cost and free are red flags for bad quality, be it information or products.