Indian almond leaves can be bought on aquabid, but most of them are over sea's so it takes for ever to get them.
2nd place is eBay, which some of the sellers are from over seas still.
3rd place is betta breedind web sites. Like bettysplendens.com but they are getting the from someone else so they mark it up you end up paying more.
The last and the place I get mine is ibcbettas.org. You have to sign up to be a member of the site, not the membership where you have to pay. It's just a membership so you can buy suff from the site.