Welcome MichelleA to our community. I have Rusty my male betta in the 2.5 gallon tank by Aqueon which I bought at PetSmart. Betta fishes love places to hide when they want to rest so make sure you get a few decorations and rinse them in warm water before you place them in your tank. As others have stated before me, Omega One Betta pellets is the one a lot of members recommend for feeding your betta.
I bought my decorations and food at PetSmart.
Make sure you get a thermometer so that you watch the water temperature. Bettas need to be in water between 78 - 82 degrees. They are tropical fish just remember that. I have the Zoo-Med which some members may say not to get but as for me, it has worked and Rusty's water temperature has always remained between 79-82 degrees; of course it may help that I live in Florida where the warm weather tends to keep my home warm too.
You need to get AQ Salt (commonly referred to as aquarium salt) just in case your male betta fish get's ich or velvet which are two of the main diseases your pet can get. There are forums on betta fish diseases on this website and of course the internet but always check the forums and sticky note FIRST for anything betta fish related. I know I have said a lot but I have learned so much on how to care for Rusty on this site.
Here is Rusty showing off his redness underneath his tank light. You will see that the warmth it gives off really makes him flare and also warms the water too; just keep an eye on the thermometer.
Take care and give us your betta's name and show pictures. We love them.