Production of He-3 is actually a major concern in the nuclear industry. It's pretty much the best medium to make a neutron detector out of because it has an enormous probability to capture a neutron. Neutron detectors are rather important for many reasons, but mostly because they're the best way to detect nuclear weapons.
He-3 is rather rare naturally and was only really produced in quantity as a byproduct of nuclear weapons fabrication. Basically nobody is making nuclear weapons these days (at least in significant quantities) and there's not really any viable source of He-3. Alternative detector media like BF3 is crappy by comparison and the only other way to make He-3 en masse is via fusion, which isn't yet feasible.
So nowadays a tube full of He-3 about the size of a typical fluorescent light can run into the $100000 range (ish, it's so rare that it isn't really sold by anybody).
Well, honestly it's hard to imagine any situation where it would be economically viable to extract He-3 from lunar regolith and bring it back to Earth any time soon and that's ignoring the fact that we still can't yet build a fusion reactor to burn it in. D-T fusion will be more practical for a long time because we can breed the fuel pretty easily by sticking lithium in a fission reactor. That same breeding reaction is the one that ultimately produces He-3 since the tritium decays into He-3, but it's way faster/easier to just use the tritium instead of waiting around for it to decay. Helium fusion also has most of the same materials issues as D-T fusion and a higher ignition temperature, so really it's not particularly ideal.
Outside of fuel for fusion, radiation detectors and a few other minor applications there's not much use for He-3. The more interesting possibility to me is the idea of extracting He-3 on the moon and keeping it there, using it to fuel a fusion reactor powering some sort of sci-fi type lunar city/port. Since it's available in relative abundance on the moon directly and doesn't have to be bred indirectly it starts to make sense as a fuel.
He-3 is rather rare naturally and was only really produced in quantity as a byproduct of nuclear weapons fabrication. Basically nobody is making nuclear weapons these days (at least in significant quantities) and there's not really any viable source of He-3. Alternative detector media like BF3 is crappy by comparison and the only other way to make He-3 en masse is via fusion, which isn't yet feasible.
So nowadays a tube full of He-3 about the size of a typical fluorescent light can run into the $100000 range (ish, it's so rare that it isn't really sold by anybody).