Here is some good advice-Don't buy a bowl, buy a tank. On initial set up the tank will need to go trough a process called Cycling, you will find all the info on different web sites. Goldfish can get huge and keeping them in a bowl will stunt there growth but will make internal organs weak. Make sure you have a good filter as goldfish are the dirtiest fish to keep and also have oxygen circulating, don't want fishies dying because of ammonia levels rising too high. Every so often check PH and nitrite levels, goldfish can survive in quite high PH levels. Add declorinator after every water change when adding water to tank. You only need to take out about 25% water every time you clean the tank because you need beneficial bacteria to keep the fish healthy. You will not need a heater to keep goldfish, as the can live in ice cold water. Hopefully this will help people thinking of getting a cheap fish, which should be treated with respect. I have been keeping my goldfish for 7 years know with no health problems. I also keep a 60 gallon tropical tank. Well that's about all folks, happy fish keeping.
Maybe I should write a book LOL.....