You aren't allowed to spend time with the parent dogs or see where they are kept.
You are told to stay put while the breeder disappears to get the dog.
The puppy acts fearful or shows signs of sickness.
The seller focuses on getting paid.
If they're pushing you to buy the animal online without first meeting it, you should be worried. A Chihuahua will be in your family for at least 13 to 20 years. Be very careful.
If you're inquiring about a purebred puppy, ask the breeder if they are registered with the AKC, CKC club and then contact the club on their phone right there and then.
Remember, a high price or a mention of "AKC or CKC papers" does not necessarily mean a healthy, quality puppy. Mostly all pet shops and pet mills have AKC papers. Breeds such as Chihuahuas, English or French bulldogs typically fetch high prices, price shouldn't be used to gauge value.
Get referrals of people who made purchases from the breeder, as well as veterinary references. Research the breed and check out references before you purchase the animal.
Find out if any complaints have been made about the breeder by calling AKC or CKC. Performing a search on the BBB's Web site.
If the breeder has a contract, read it before you sign. Don't be swayed by a written promise to take the dog back and give you a replacement if the original falls ill.
If you want a puppy, don't buy one online. That's the short answer to avoiding the heartache of paying hundreds or even thousands of dollars for a puppy that never arrives, getting a different one than the one you ordered or, worst of all, getting a puppy that becomes ill and dies.