I found New Life Spectrum Betta pellets on Amazon.com
The betta is in a 5 gallon tank with one snail, and I have a larger tank with neon tetras, cherry barbs, Endlers and pygmy Cory and I also got NLS Small Fish Formula from them. Amazon has lots of stuff for fish.
I'd say the pellets I have are about the size of a poppy seed - like you find on bagels.
I alternate between NLS, Hikari and Omega One pellets. The NLS and Hikari are half the size of the Omega one pellets. I also give thawed frozen brine shrimp and blood worms a couple times a week.
My betta was really thin when I got him, and young. I've had him 3 months now, and he has really grown. He's still looks thin compared to the photos of bettas I see on AquaBid. I feed 4-5 around 8 am and 8 pm, and a couple in the middle of the day. The Omega pellets are bigger, so only 2 or 3 of them at a time. I'm sure people would say I am over feeding, but this guy is very active in a 5 gallon planted tank, and has not had any problems at all. Once he finishes growing and filling out, I will cut him back a bit. Probably to 2 pellets 3 times a day. I hear such good things about the New Life Spectrum that I will probably feed just those pellets in the future when I use up the other 2 brands. Took me a while to find the NLS pellets, didn't have them locally that I could find.
But I am pretty new at keeping fish (well had them back when I was a kid - 40 years ago) .... so keep that in mind...