If you find a tank that comes with the hood, you can get florescent bulbs for the hood that will support live plants, should you choose to add some. As for plants, anubias can simply be floated in the water. They are super hardy, and bettas love using them as beds and lounge chairs.
Water conditioner: Prime by Seachem is recommended here because it detoxifies ammonia and is very concentrated. It's an invaluable tool before your tank cycles, as well.
Do get the API Freshwater Master test kit so you can keep an eye on your water chemistry. You'll especially need to watch ammonia until your tank cycles. If you want to speed the cycling process along you can add a small bottle of Tetra Safe Start.
For 10 gallons, your heater should be 50 watts and adjustable. Remember to get a thermometer, too.
The sponge filter will need an air pump, tubing, and backflow check valve.
Quality food: New Life Spectrum pellets or Omega One Betta Buffet pellets are the 2 most recommended here. Do not buy the dried bloodworm treats; they tend to cause digestive problems.
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