Goldfish bowls make great 'floating flower' vases. They are absolutely useless for keeping fish in. The first rule of fish keeping is "1 inch of fish needs a minimum of 1 Gallon of water". Goldfish bowls are therefore not large enough to house one tiny fish.
A fish bowl is not a solution its what you keep your goldfish/ beta fish in :P
it depends how big the fish bowl is
If it is as old as a goldfish that can, it can.
The cheapest way to keep a goldfish is to keep it in a fish bowl.........as long as the bowl is big enough the fish will be happy there.
Yes, provided the bowl is large enough.
A fish needs 20 litres in a bowl
Yes, like all pet fish, goldfish need more oxygen than can be provided by just a bowl of water.
The water in a goldfish bowl should be changed at least once a week to maintain the health of the fish.
It should be fine.
Bettas are. Goldfish really should have an aquarium if you want them to live.
Zero, goldfish need very clean cool water and are very dirty fish.
No, for a number of reasons. Firstly, one goldfish needs at least 20 gallons on it's own. In addition, not only are bettas and goldfish not compatible, but their needs are different including foods and water temperature; Bettas are best as a solitary fish.