When most people think of dog kennels they think of dog kennels and boarding places. That is not the only kind. A lot of people swear by potty training puppies with a large dog kennel that turns into their safe area for bed time and when they are scared or in trouble.
If you are looking for a way to contain your dog in an unfenced area, use a chain link dog kennel from as small as 4 feet by 4 feet all the way up to a large dog kennel run that can be 20 feet by 20 feet. In some counties where you are limited by how many dogs you may own, you can add a dog kennel run with enough area for each dog and you can be permitted to have more dogs. This applies to small and large dogs.
Other people use portable dog kennels to take their small dogs or cats to the vets for safety and it helps keep the cats calmer. large dog kennels can be put in the back of a truck to transport bigger dogs safely in an open bed of a truck. Plus water and bird fowl hunters will have similar dogs kennel in the truck year round to house their dogs on the way to and from hunting trips.
If you are looking for a dog kennel they can be pricey so first look through your local classifieds for dog kennels for sale and even on eBay. You may find that it is worth the search in the amount you save.