The basics ~ a Betta needs at LEAST a 1 gallon tank, preferably 2-5 gallons with 2-4 live or silk (not plastic) plants and a cave or two to hide in ! If the tank does not have a small filter, you'll need to completely clean it and change the water once every 7-9 days to keep you Betta healthy. Use StressCoat (cheap, and they sell it everywhere that they have fish!) to dechlor the water... you definitely need it. My Bettas also appreciate a pinch of aquarium salt each time I change their water. Put a small thermometer (costs $.79 at Wal*Mart) in the tank, the water should be 75*-80* ideally, though they can live with 70* at the coldest. For food, Hikari Betta Pellets are excellent! HBH Betta Bites also work very well, and only cost $2 for a bottle that will last forEVER. ^-^ Feed around 4 pellets twice a day. Their diet should be supplemented at least a couple times a week with thawed-out frozen bloodworms.

My last Betta lived to be over 3 years old... I suggest you try to get a Betta from a nice Fish or Feed Store, as they tend to be younger and better cared for... their jars should be big enough for them to have some room to swim, and they should be VERY clean! Look for a Betta with nice full fins (NO tears or jagged edges), bright coloring, and preferably one that is "flaring", or spreading his fins.