As you probably already know, the Bagle Hound is a somewhat rare dog breed. It is unlikely that you will find bagle puppies for sale at your local rescue or pet store. Your best opportunity for finding bagle hounds would be classified ads and bagle hound breeders. If you do stumble across a bagle hound at a pet store or rescue they will likely be listed as a "basset hound beagle mix".
When looking through classified ads and/or craigslist, keep in mind that many sellers may not list their dogs as "bagle hounds" (since most people are unfamiliar with the breed name). They will likely be listed as "beagle basset mix", "basset mix", or "beagle mix". Of course, you should always double check the breed's bloodline before meeting the seller.
Breeders are a good choice when searching for a bagle hound puppies. Most bagle hound breeders will also be Beagle breeders and Basset Hound breeders (since those are more popular dog breeds). Getting a Bagle from a breeder is a good choice since the breeder will be familiar with both parent breeds and will be able to give you detailed information about the breed and what to expect. Plus, you can have the opportunity to meet the parents which can give you insight to the traits your dog may inherit (if both parents are large the chances are their offspring will also be large).