1) Seconding used as an option from the other post. That's great. 2) Big Buckets of legos still exist and are pretty cheap, actually. 3) Kids may like the set

1) Seconding used as an option from the other post. That's great. 2) Big Buckets of legos still exist and are pretty cheap, actually. 3) Kids may like the sets on the shelf but my kids have treated them like puzzles: they're really excited when they get them and put them together once, play with them barely if at all, then as soon as they get a little messed up, just destroy them and go back to making whatever, and never put them together again. I've seen very few modern sets (but there are a few!) that look like they'd support the play-style I had as a kid. Even the "big" sets with huge part counts are tiny compared to large 90s sets, and have rooms and such that are almost too small even for kid-hands to play in, plus the aforementioned problems with so many of the pieces being tiny, so much of the construction being really fiddly (relying on all those tiny pieces) rather than straightforward so it's hard to fix if part of it gets broken, or you deliberately disassemble part of it for some reason. Few exposed studs plus the fiddly-construction thing makes expansion/customization and "kit-bashing" tougher, which was a big part of what I did. I suppose the modern ones appeal really well to kids who like to assemble lego sets, then display them, rather than playing with them. I knew a few kids like when I was a kid. I don't know whether 3d printed lego replacements are any good.