Lol funnily enough, the crypt that I have that has flourished the most, like the ones in your pic, was a 'rescue' from a long neglected tank, just a few thin scraggly leaves, coated in a horrible black algae/diatom mess. By the time those had been removed, it was just a sad little bunch of roots. Stuck in my gravel anyway, just to see, and it's one of my best plants! Have a few other crypts now too, and I agree, under-rated plants that can look great.
Different sands seem to be more available in the US, or I'm just not looking in the right places. I can't afford lots of fancy substrate either, my tanks are second hand and I've just the substrate that came with them. But since I'm having to revamp them to move them, I'm putting some thought into the substrates I want. One tank came with a 5kg bag of the natural pale sand, and might be enough for my ten gallon. The only play sand I've found that's aquarium safe is only £5 for 15 kg, so that will go in a 15 gallon
https://www.argos.co.uk/product/3650574
And the other 15 gallon is what I'm looking for a darker substrate for. I'd rather get a substrate I'd like and continue gathering wood and rocks from the wild to save on expenses.