Pitluvs is right, they do kind of choose you haha. One will tug at your heart strings particularly hard and you'll know right away =) The halfmoons aren't that expensive at petco, only about $12 (atleast that's what it says on the website). If you wanted one a bit cheaper, i think they sell them for 8 or 10 at petsmart, and they are just as pretty as the ones at petco. But petsmart doesn't have as good of a selection of females XP
My Current bettas:
Sullivan- Orange rose tail halfmoon male
Daisy- Mustard Gas (black and yellow) veil tail female
Milton- Teal butterfly halfmoon male (mom's betta)
DFTBA to nerdfighters working to decrease world suck!