Properly cared for betta (Siamese Fighter Fish) can live up to 5~7 years or even longer.
If you truly like betta, you do not need to spend a lot of money at all.
Keep in mind that betta needs to be kept alone. You will need just one small size tank. 5 gallons is minimal, 10 gallon is recommended. More water means more stable water temperature and chemistry, and fish need stable water to thrive.
At my local stores,
5-gallon glass tank = $11
10-gallon glass tank = $14
I would definitely go for the 10-gallon, because it is $3 more for double the size.
You will need a heater because betta is tropical fish.
I would recommend adjustable heater, because most heaters out there aren't exactly accurate. You will need to adjust the temperature accordingly. Betta requires 78~80F+ to be healthy. Lower temperature will compromise their immune system, which can make them easier to catch diseases and become sick.
A
50w heater will work just fine.
A filter system is a must for any fish. It is explained in the article of aquarium nitrogen cycle. Without it, fish will die to ammonia poisoning.
For small sized tanks,
AquaClear Power Filter will do fine. However, for a 10 gallon, even the smallest AquaClear 20 might create too strong of a current for a slow moving fish like betta, because it has the GPH (gallon per hour) rate of 100 gallons. You may try to slow the current by install a piece of
pre-filter on the intake.
Or,
You can just use a sponge filter instead of the power filter. It will not have strong current, but you will need either an air pump or a powerhead to power the sponge filter in order to have it to work.
You may choose between
Hydro Sponge filter, and
Azoo Oxygen Plus Bio-Filters. Make sure try to get a Hydro Sponge I if you go that brand, because any other model is too high for a 10 gallon and require manual cutting of the tube before it can fit.
You will also need water conditioner.
SeaChem Prime is my favorite.
As well as fish food. For small mouth fish like betta, you should get small pellets. I like
New Life Spectrum. Use the "small fish formula".
For water change (weekly 30~50% partial water change is recommended as regular maintenance),
Extra equipments you will need will be a 5-gallon bucket, or maybe two.
An aquarium vacuum. A fish net. Algae scraper.
Of course, it is recommended you do a fishless cycle first before adding the fish. It will need additional supplies. Ammonia and a water test kit are must have. It is up to you if you want to get Tetra SafeStart to speed it up. Sure you can skip the fishless cycle if you use Tetra SafeStart the moment you get fish. Everything in this paragraph is explained in the
aquarium nitrogen cycle article.
This whole set up should be below $100, and you will not need to spend money again for a long time to come.
The bright side of this set up is cheap, easy to maintain. Although you only get 1 betta fish, it is not a downside if you like it.
