Totally! I had the same thing happen with a fancy kitchen gadget last year. The instructions were basically just "cook things with it." No tips, no real guide, nothing. It felt like such a rip-off. I used it twice and now it just takes up a whole cabinet. Your buddy nailed the feeling.
Dang that really stinks, sorry you got burned on that. Its so frustrating when you pay good money and basically get nothing back, like hey here is what you could have googled yourself. The kitchen gadget comparison is perfect, all hype and no real help once you actually try to use it. Have you tried just looking up free prompt libraries on GitHub or something? Sometimes the community ones are way better than the paid stuff.