Originally Posted by bamsuddenimpact
Try Aqueon Betta Food. They are really tiny pellets and like 2-3$. My fish love them and they fit in their mouths
Yes! Try these. I swear by these. Both Philson and Leopold love them! They're great too because they can float for a little bit or be easily sunk! Philson is a normal acting betta and eats his pellets at the top, so he gobbles them up. Leopold, however, will only eat his pellets if he gets to chase them first (he's a strange one, but I love him), so I can easily sink these pellets and he thinks they're great. They are also very small, so a young betta can easily eat them. Plus, from one college betta owner to another, they are super cheap :)
On the heater front, I own two 25W submersible elite heaters. They keep my 1g and 1.5g and a lovely 78F, and that's on a very low setting. It should certainly do the trick for your 3g. You can find them on Amazon for about $15.