This page is for some of the betta products that i have seen for bettas for the best or worest.
Jungle buddies - I personally like jungle buddies products. Not only for bettas for general fishkeeping. They are easy, fast, and provide basically no human error. Medications such as "paracite clear" or "fungus clear" are great for treating fish and are so easy. The make plenty of water conditioners as well.
Stress coat - Another great all fish product. I use it after everywater change or just illness prevention. It helps the fish gain slime coat which is important for disease prevention. At the same time it helps remove chlorine from the water. Great product.
Betta Water - This may be a good product, but i haven't tried it or needed it. I would have to say it would be a waste of money for most, but good if your tap water is extremely bad for fish. How ever i have been fine using tap water and stress coat or water that has been sitting out for awhile.
Betta bio-gold - One of my favorite betta foods. Hikari has done great when it comes to this food.