Both halfmoons are absolutely stunning. I'd cut off my arm to get either of them! Anyways, the white is obviously a lot rarer, but also a lot more expensive. Are you planning to breed? If you are, both colors are hard, but the white probably harder (red wash). Sooo... depends on what you want it for!
If you are new to bettas, get the cheapest one you can get - the $3 petstore betta. If you can take care of him, then you can move on to a more expensive betta. Plus, those nie pricey ones are for those who wish to breed, not just to keep as a pet. Otherwise, it would be a waste.