You can raise your own live food, people raise things like grindal worms, vinegar eels, and brine shrimp. I've also heard of people setting containers of water outside for mosquitoes to breed in, they then get the larvae out the water and feed them to their betta. If you do the last please do not let the larvae turn into mosquitoes!
Another option is to feed a variety of frozen foods, like brine shrimp, mysis shrimp, blood worms, and daphnia.
Betta are insectivores and have no need of vegges, so don't feed them that.
I rotate between frozen bloodworms, frozen brine shrimp, Fluval Bug Bites, and New Life Spectrum Betta Naturox. Each day they get something different.