There are massive regulations on orbiting/deorbiting radioactive materials thus selling lunar mined h-3 to earth isnt very easy, and there are regulations against having nuclear reactors/bombs in space so making a reactor on the moon and selling to it/selling its energy is also not very possible.
Basically once all this is set up its possible, however currently simply mining stuff like iron, platinum, gold, etc from asteroids which are easier to get to in the first place is much easier.
Also:
Helium is present in the lunar regolith in quantities of ten to a hundred (weight) parts per million, and 0.003 to 1 percent of this amount (depending on soil). 2006 market price for He3 was about $46,500 per troy ounce ($1500/gram, $1.5M/kg), more than 120 times the value per unit weight of Gold and over eight times the value of Rhodium.
Thats alot of strip mining :/