Catch a cricket outside, look on the internet to find what they look like if you don't know. Find one of any size that only has two hairy protrusions in the back. This is a male. The female has an ovipositor which lays her eggs for her. Males sing and sound just like a canary. If your cricket does not sing at night, then let it go and get another one. They eat a potato slice for food, a little Coke top full of water and paper towel. They love bread and vegetables.
Cleaning is a snap, they don't bite and they are not any problem to keep. You can buy them for ten cents at the local pet store, but I like to catch my own. Do not put two together, they will kill one another. Have fun!
They will only kill each other of they don't have enough food. They also eat vegetables, cereal, and corn meal.
I have been keeping the common "house cricket" (the kind they sell at pet stores as food for other creatures) as pets for about six months, mostly because I love their beautiful music. I usually have no more than four or five at a time, but they only live about 4-8 weeks as adults so I often have to buy more.
It isn't true (at least for this type of cricket) that they will kill each other if you put two together. Mine never have, and the pet stores keep dozens of them together all the time. The key to keeping them from doing that is to always have food available for them. They only kill each other if no other food is available.
It is also a very common misconception that only the males sing. Adult females are very easy to identify by the long ovipositor extending between the two back legs, and I have witnessed virtually all of my adult females singing. The adult males sing too, of course, but the females' music is actually even more "musical" than that of the males! You can tell which one is singing by watching their wings-- they rub one wing back and forth over the other, sort of like playing a violin.
Another fun thing to do is buy a little cricket house. They are small little cages, some made from wood and some very ornate and made of beautiful metal.